Fractions

fraction class7 selina

Step by Step solutions of Concise Mathematics ICSE Class-7 Maths chapter 3- Fractions by Selina is provided.

Table of Contents

Exercise: 3-C

Q1: Reduce to a single fraction:

i. \(\frac{1}{2} + \frac{2}{3}\)

Step 1: Find the LCM of 2 and 3, which is 6.
Step 2: Convert each fraction to have a denominator of 6:
\(\frac{1}{2} = \frac{3}{6}, \quad \frac{2}{3} = \frac{4}{6}\)
Step 3: Add the fractions: \(\frac{3}{6} + \frac{4}{6} = \frac{7}{6}\)
Answer: \(\frac{7}{6} = 1\frac{1}{6}\)

ii. \(\frac{3}{5} – \frac{1}{10}\)

Step 1: Find the LCM of 5 and 10, which is 10.
Step 2: Convert each fraction to have a denominator of 10:
\(\frac{3}{5} = \frac{6}{10}, \quad \frac{1}{10} = \frac{1}{10}\)
Step 3: Subtract the fractions: \(\frac{6}{10} – \frac{1}{10} = \frac{5}{10} = \frac{1}{2}\)
Answer: \(\frac{1}{2}\)

iii. \(\frac{2}{3} – \frac{1}{6}\)

Step 1: Find the LCM of 3 and 6, which is 6.
Step 2: Convert each fraction to have a denominator of 6:
\(\frac{2}{3} = \frac{4}{6}, \quad \frac{1}{6} = \frac{1}{6}\)
Step 3: Subtract the fractions: \(\frac{4}{6} – \frac{1}{6} = \frac{3}{6} = \frac{1}{2}\)
Answer: \(\frac{1}{2}\)

iv. \(1\frac{1}{3} + 2\frac{1}{4}\)

Step 1: Convert the mixed fractions to improper fractions:
\(1\frac{1}{3} = \frac{4}{3}, \quad 2\frac{1}{4} = \frac{9}{4}\)
Step 2: Find the LCM of 3 and 4, which is 12.
Step 3: Convert the fractions to have a denominator of 12:
\(\frac{4}{3} = \frac{16}{12}, \quad \frac{9}{4} = \frac{27}{12}\)
Step 4: Add the fractions: \(\frac{16}{12} + \frac{27}{12} = \frac{43}{12}\)
Answer: \(\frac{43}{12} = 3\frac{7}{12}\)

v. \(\frac{1}{4} + \frac{5}{6} – \frac{1}{12}\)

Step 1: Find the LCM of 4, 6, and 12, which is 12.
Step 2: Convert each fraction to have a denominator of 12:
\(\frac{1}{4} = \frac{3}{12}, \quad \frac{5}{6} = \frac{10}{12}, \quad \frac{1}{12} = \frac{1}{12}\)
Step 3: Add and subtract the fractions: \(\frac{3}{12} + \frac{10}{12} – \frac{1}{12} = \frac{12}{12} = 1\)
Answer: \(1\)

vi. \(\frac{2}{3} – \frac{3}{5} + 3 – \frac{1}{5}\)

Step 1: Convert the whole number 3 to a fraction: \(3 = \frac{15}{5}\)
Step 2: Find the LCM of 3, 5, and 5, which is 15.
Step 3: Convert each fraction to have a denominator of 15:
\(\frac{2}{3} = \frac{10}{15}, \quad \frac{3}{5} = \frac{9}{15}, \quad 3 = \frac{45}{15}, \quad \frac{1}{5} = \frac{3}{15}\)
Step 4: Perform the addition and subtraction: \(\frac{10}{15} – \frac{9}{15} + \frac{45}{15} – \frac{3}{15} = \frac{43}{15}\)
Answer: \(\frac{43}{15} = 2\frac{13}{15}\)

vii. \(\frac{2}{3} – \frac{1}{5} + \frac{1}{10}\)

Step 1: Find the LCM of 3, 5, and 10, which is 30.
Step 2: Convert each fraction to have a denominator of 30:
\(\frac{2}{3} = \frac{20}{30}, \quad \frac{1}{5} = \frac{6}{30}, \quad \frac{1}{10} = \frac{3}{30}\)
Step 3: Add and subtract the fractions: \(\frac{20}{30} – \frac{6}{30} + \frac{3}{30} = \frac{17}{30}\)
Answer: \(\frac{17}{30}\)

viii. \(2\frac{1}{2} + 2\frac{1}{3} – 1\frac{1}{4}\)

Step 1: Convert the mixed fractions to improper fractions:
\(2\frac{1}{2} = \frac{5}{2}, \quad 2\frac{1}{3} = \frac{7}{3}, \quad 1\frac{1}{4} = \frac{5}{4}\)
Step 2: Find the LCM of 2, 3, and 4, which is 12.
Step 3: Convert each fraction to have a denominator of 12:
\(\frac{5}{2} = \frac{30}{12}, \quad \frac{7}{3} = \frac{28}{12}, \quad \frac{5}{4} = \frac{15}{12}\)
Step 4: Perform the addition and subtraction: \(\frac{30}{12} + \frac{28}{12} – \frac{15}{12} = \frac{43}{12}\)
Answer: \(\frac{43}{12} = 3\frac{7}{12}\)

ix. \(2\frac{5}{8} – 2\frac{1}{6} + 4\frac{3}{4}\)

Step 1: Convert the mixed fractions to improper fractions:
\(2\frac{5}{8} = \frac{21}{8}, \quad 2\frac{1}{6} = \frac{13}{6}, \quad 4\frac{3}{4} = \frac{19}{4}\)
Step 2: Find the LCM of 8, 6, and 4, which is 24.
Step 3: Convert each fraction to have a denominator of 24:
\(\frac{21}{8} = \frac{63}{24}, \quad \frac{13}{6} = \frac{52}{24}, \quad \frac{19}{4} = \frac{114}{24}\)
Step 4: Perform the subtraction and addition: \(\frac{63}{24} – \frac{52}{24} + \frac{114}{24} = \frac{125}{24}\)
Answer: \(\frac{125}{24} = 5\frac{5}{24}\)


Q2: Simplify:

i. \(\frac{3}{4} \times 6\)

Step 1: Multiply the fraction by the whole number:
\(\frac{3}{4} \times 6 = \frac{3 \times 6}{4} = \frac{18}{4} = \frac{9}{2}\)
Answer: \(\frac{9}{2} = 4\frac{1}{2}\)

ii. \(\frac{2}{3} \times 15\)

Step 1: Multiply the fraction by the whole number:
\(\frac{2}{3} \times 15 = \frac{2 \times 15}{3} = \frac{30}{3} = 10\)
Answer: \(10\)

iii. \(\frac{3}{4} \times \frac{1}{2}\)

Step 1: Multiply the fractions:
\(\frac{3}{4} \times \frac{1}{2} = \frac{3 \times 1}{4 \times 2} = \frac{3}{8}\)
Answer: \(\frac{3}{8}\)

iv. \(\frac{9}{12} \times \frac{4}{7}\)

Step 1: Multiply the fractions:
\(\frac{9}{12} \times \frac{4}{7} = \frac{9 \times 4}{12 \times 7} = \frac{36}{84}\)
Step 2: Simplify the fraction:
\(\frac{36}{84} = \frac{3}{7}\)
Answer: \(\frac{3}{7}\)

v. \(45 \times 2\frac{1}{3}\)

Step 1: Convert the mixed number to an improper fraction:
\(2\frac{1}{3} = \frac{7}{3}\)
Step 2: Multiply the whole number by the fraction:
\(45 \times \frac{7}{3} = \frac{45 \times 7}{3} = \frac{315}{3} = 105\)
Answer: \(105\)

vi. \(36 \times 3\frac{1}{4}\)

Step 1: Convert the mixed number to an improper fraction:
\(3\frac{1}{4} = \frac{13}{4}\)
Step 2: Multiply the whole number by the fraction:
\(36 \times \frac{13}{4} = \frac{36 \times 13}{4} = \frac{468}{4} = 117\)
Answer: \(117\)

vii. \(2 \div \frac{1}{3}\)

Step 1: Divide by a fraction by multiplying by its reciprocal:
\(2 \div \frac{1}{3} = 2 \times \frac{3}{1} = 6\)
Answer: \(6\)

viii. \(3 \div \frac{2}{5}\)

Step 1: Divide by a fraction by multiplying by its reciprocal:
\(3 \div \frac{2}{5} = 3 \times \frac{5}{2} = \frac{15}{2}\)
Answer: \(\frac{15}{2} = 7\frac{1}{2}\)

ix. \(1 \div \frac{3}{5}\)

Step 1: Divide by a fraction by multiplying by its reciprocal:
\(1 \div \frac{3}{5} = 1 \times \frac{5}{3} = \frac{5}{3}\)
Answer: \(\frac{5}{3} = 1\frac{2}{3}\)

x. \(\frac{1}{3} \div \frac{1}{4}\)

Step 1: Divide by a fraction by multiplying by its reciprocal:
\(\frac{1}{3} \div \frac{1}{4} = \frac{1}{3} \times \frac{4}{1} = \frac{4}{3}\)
Answer: \(\frac{4}{3} = 1\frac{1}{3}\)

xi. \(-\frac{5}{8} \div \frac{3}{4}\)

Step 1: Divide by a fraction by multiplying by its reciprocal:
\(-\frac{5}{8} \div \frac{3}{4} = -\frac{5}{8} \times \frac{4}{3} = -\frac{20}{24} = -\frac{5}{6}\)
Answer: \(-\frac{5}{6}\)

xii. \(3\frac{3}{7} \div 1\frac{1}{14}\)

Step 1: Convert the mixed numbers to improper fractions:
\(3\frac{3}{7} = \frac{24}{7}, \quad 1\frac{1}{14} = \frac{15}{14}\)
Step 2: Divide by a fraction by multiplying by its reciprocal:
\(\frac{24}{7} \div \frac{15}{14} = \frac{24}{7} \times \frac{14}{15} = \frac{336}{105} = \frac{16}{5}\)
Answer: \(\frac{16}{5} = 3\frac{1}{5}\)

xiii. \(3\frac{3}{4} \times 1\frac{1}{5} \times \frac{20}{21}\)

Step 1: Convert the mixed numbers to improper fractions:
\(3\frac{3}{4} = \frac{15}{4}, \quad 1\frac{1}{5} = \frac{6}{5}\)
Step 2: Multiply the fractions:
\(\frac{15}{4} \times \frac{6}{5} = \frac{90}{20} = \frac{9}{2}\)
Step 3: Multiply by \(\frac{20}{21}\):
\(\frac{9}{2} \times \frac{20}{21} = \frac{180}{42} = \frac{30}{7}\)
Answer: \(\frac{30}{7} = 4\frac{2}{7}\)


Q3: Subtract:

i. \(2\ from\ \frac{2}{3}\)

Step 1: Subtract the whole number from the fraction:
\(\frac{2}{3} – 2 = \frac{2}{3} – \frac{6}{3} = \frac{2 – 6}{3} = \frac{-4}{3}\)
Answer: \(\frac{-4}{3} = -1\frac{1}{3}\)

ii. \(\frac{1}{8}\ from\ \frac{5}{8}\)

Step 1: Subtract the fractions with equal denominators:
\(\frac{5}{8} – \frac{1}{8} = \frac{5 – 1}{8} = \frac{4}{8} = \frac{1}{2}\)
Answer: \(\frac{1}{2}\)

iii. \(-\frac{2}{5}\ from\ \frac{2}{5}\)

Step 1: Subtract the fractions:
\(\frac{2}{5} – (-\frac{2}{5}) = \frac{2}{5} + \frac{2}{5} = \frac{4}{5}\)
Answer: \(\frac{4}{5}\)

iv. \(-\frac{3}{7}\ from\ \frac{3}{7}\)

Step 1: Subtract the fractions:
\(\frac{3}{7} – (-\frac{3}{7}) = \frac{3}{7} + \frac{3}{7} = \frac{6}{7}\)
Answer: \(\frac{6}{7}\)

v. \(0\ from\ -\frac{4}{5}\)

Step 1: Subtract 0 from the fraction:
\(-\frac{4}{5} – 0 = -\frac{4}{5}\)
Answer: \(-\frac{4}{5}\)

vi. \(\frac{2}{9}\ from\ \frac{4}{5}\)

Step 1: Make the denominators equal by finding the LCM of 9 and 5, which is 45:
\(\frac{4}{5} = \frac{36}{45}, \quad \frac{2}{9} = \frac{10}{45}\)
Step 2: Subtract the fractions with equal denominators:
\(\frac{36}{45} – \frac{10}{45} = \frac{36 – 10}{45} = \frac{26}{45}\)
Answer: \(\frac{26}{45}\)

vii. \(-\frac{4}{7}\ from\ -\frac{6}{11}\)

Step 1: Make the denominators equal by finding the LCM of 7 and 11, which is 77:
\(-\frac{4}{7} = -\frac{44}{77}, \quad -\frac{6}{11} = -\frac{42}{77}\)
Step 2: Subtract the fractions with equal denominators:
\(-\frac{42}{77} – (-\frac{44}{77}) = -\frac{42}{77} + \frac{44}{77} = \frac{-42 + 44}{77} = \frac{2}{77}\)
Answer: \(\frac{2}{77}\)


Q4: Find the value of:

i. \(\frac{1}{2}\ of\ 10\) kg

Step 1: Multiply the fraction by the given value:
\(\frac{1}{2} \times 10 = \frac{10}{2} = 5\) kg
Answer: 5 kg

ii. \(\frac{3}{5}\ of\ 1\) hours

Step 1: Multiply the fraction by the given value:
\(\frac{3}{5} \times 1 = \frac{3}{5}\) hours \(= \frac{3 \times 60}{5} = 36\) minutes
Answer: \(\frac{3}{5}\) hours or \(\frac{3 \times 60}{5} = 36\) minutes

iii. \(\frac{4}{7}\ of\ 2\frac{1}{3}\) kg

Step 1: Convert the mixed fraction to an improper fraction:
\(2\frac{1}{3} = \frac{7}{3}\)
Step 2: Multiply the fraction by the given value:
\(\frac{4}{7} \times \frac{7}{3} = \frac{28}{21} = \frac{4}{3}\) kg
Answer: \(\frac{4}{3}\) kg or 1\(\frac{1}{3}\) kg

iv. \(3\frac{1}{2}\ times\ of\ 2\) metre

Step 1: Convert the mixed fraction to an improper fraction:
\(3\frac{1}{2} = \frac{7}{2}\)
Step 2: Multiply the fraction by the given value:
\(\frac{7}{2} \times 2 = \frac{14}{2} = 7\) metres
Answer: 7 metres

v. \(\frac{1}{2}\ of\ 2\frac{2}{3}\)

Step 1: Convert the mixed fraction to an improper fraction:
\(2\frac{2}{3} = \frac{8}{3}\)
Step 2: Multiply the fraction by the given value:
\(\frac{1}{2} \times \frac{8}{3} = \frac{8}{6} = \frac{4}{3}\)
Answer: \(\frac{4}{3}\) or 1\(\frac{1}{3}\)

vi. \(\frac{5}{11}\ of\ \frac{4}{5}\ of\ 22\) kg

Step 1: First, calculate \(\frac{4}{5}\ of\ 22\):
\(\frac{4}{5} \times 22 = \frac{88}{5} = 17\frac{3}{5}\) kg
Step 2: Multiply \(\frac{5}{11}\) by 17\(\frac{3}{5}\):
\(\frac{5}{11} \times 17\frac{3}{5} = \frac{5}{11} \times \frac{88}{5} = \frac{440}{55} = 8\) kg
Answer: 8 kg


Q5: Simplify and reduce to a simple fraction:

i. \(\frac{3}{3\frac{3}{4}}\)

Step 1: Convert the mixed fraction in the denominator to an improper fraction:
\(3\frac{3}{4} = \frac{15}{4}\)
Step 2: Simplify the division:
\(\frac{3}{\frac{15}{4}} = 3 \times \frac{4}{15} = \frac{12}{15}\)
Step 3: Reduce to lowest terms:
\(\frac{12}{15} = \frac{4}{5}\)
Answer: \(\frac{4}{5}\)

ii. \(\frac{\frac{3}{5}}{7}\)

Step 1: Convert the division into multiplication by the reciprocal:
\(\frac{3}{5} \div 7 = \frac{3}{5} \times \frac{1}{7} = \frac{3}{35}\)
Answer: \(\frac{3}{35}\)

iii. \(\frac{3}{\frac{5}{7}}\)

Step 1: Convert the division into multiplication by the reciprocal:
\(\frac{3}{\frac{5}{7}} = 3 \times \frac{7}{5} = \frac{21}{5}\)
Answer: \(\frac{21}{5}\) or \(4\frac{1}{5}\)

iv. \(\frac{2\frac{1}{5}}{1\frac{1}{10}}\)

Step 1: Convert the mixed fractions to improper fractions:
\(2\frac{1}{5} = \frac{11}{5},\ 1\frac{1}{10} = \frac{11}{10}\)
Step 2: Divide the fractions:
\(\frac{11}{5} \div \frac{11}{10} = \frac{11}{5} \times \frac{10}{11} = \frac{110}{55} = 2\)
Answer: 2

v. \(\frac{2}{5}\ of\ \frac{6}{11}\times1\frac{1}{4}\)

Step 1: Convert the mixed fraction to an improper fraction:
\(1\frac{1}{4} = \frac{5}{4}\)
Step 2: Multiply the fractions:
\(\frac{2}{5} \times \frac{6}{11} = \frac{12}{55}\)
\(\frac{12}{55} \times \frac{5}{4} = \frac{60}{220} = \frac{3}{11}\)
Answer: \(\frac{3}{11}\)

vi. \(2\frac{1}{4}\div\frac{1}{7}\times\frac{1}{3}\)

Step 1: Convert the mixed fraction to an improper fraction:
\(2\frac{1}{4} = \frac{9}{4}\)
Step 2: Divide and multiply the fractions:
\(\frac{9}{4} \div \frac{1}{7} = \frac{9}{4} \times \frac{7}{1} = \frac{63}{4}\)
\(\frac{63}{4} \times \frac{1}{3} = \frac{63}{12} = \frac{21}{4}\)
Answer: \(\frac{21}{4}\) or \(5\frac{1}{4}\)

vii. \(\frac{1}{3}\times4\frac{2}{3}\div3\frac{1}{2}\times\frac{1}{2}\)

Step 1: Convert the mixed fractions to improper fractions:
\(4\frac{2}{3} = \frac{14}{3},\ 3\frac{1}{2} = \frac{7}{2}\)
Step 2: Perform the operations step by step:
\(\frac{1}{3} \times \frac{14}{3} = \frac{14}{9}\)
\(\frac{14}{9} \div \frac{7}{2} = \frac{14}{9} \times \frac{2}{7} = \frac{28}{63} = \frac{4}{9}\)
\(\frac{4}{9} \times \frac{1}{2} = \frac{4}{18} = \frac{2}{9}\)
Answer: \(\frac{2}{9}\)

viii. \(\frac{2}{3}\times1\frac{1}{4}\div\frac{3}{7}\ of\ 2\frac{5}{8}\)

Step 1: Convert the mixed fractions to improper fractions:
\(1\frac{1}{4} = \frac{5}{4},\ 2\frac{5}{8} = \frac{21}{8}\)
Step 2: Perform the operations step by step:
\(\frac{3}{7}\ of\ 2\frac{5}{8} = \frac{3}{7} \times \frac{21}{8} = \frac{63}{56} = \frac{9}{8}\)
\(1\frac{1}{4} \div \frac{9}{8} = \frac{5}{4} \div \frac{9}{8} = \frac{5}{4} \times \frac{8}{9} = \frac{40}{36} = \frac{10}{9}\)
\(\frac{2}{3} \times \frac{10}{9} = \frac{20}{27}\)
Answer: \(\frac{20}{27}\)

ix. \(0\div\frac{8}{11}\)

Step 1: Any number divided by a non-zero number is 0.
Answer: 0

x. \(\frac{4}{5}\div\frac{7}{15}\ of\ \frac{8}{9}\)

Step 1: Multiply the fractions:
\(\frac{7}{15} \ of\frac{8}{9} = \frac{7}{15} \times \frac{8}{9} = \frac{56}{135}\)
Step 2: Divide the fractions:
\(\frac{4}{5} \div \frac{56}{135} = \frac{4}{5} \times \frac{135}{56} = \frac{540}{280} = \frac{27}{14}\)
Answer: \(\frac{27}{14}\) or \(1\frac{13}{14}\)

xi. \(\frac{4}{5}\div\frac{7}{15}\times\frac{8}{9}\)

Step 1: Divide the fractions:
\(\frac{4}{5} \div \frac{7}{15} = \frac{4}{5} \times \frac{15}{7} = \frac{60}{35} = \frac{12}{7}\)
Step 2: Multiply by \(\frac{8}{9}\):
\(\frac{12}{7} \times \frac{8}{9} = \frac{96}{63} = \frac{32}{21}\)
Answer: \(\frac{32}{21}\) or \(1\frac{11}{21}\)

xii. \(\frac{4}{5}\ of\ \frac{7}{15}\div\frac{8}{9}\)

Step 1: Find \(\frac{4}{5}\) of \(\frac{7}{15}\):
\(\frac{4}{5} \times \frac{7}{15} = \frac{28}{75}\)
Step 2: Divide by \(\frac{8}{9}\):
\(\frac{28}{75} \div \frac{8}{9} = \frac{28}{75} \times \frac{9}{8} = \frac{252}{600} = \frac{21}{50}\)
Answer: \(\frac{21}{50}\)

xiii. \(\frac{1}{2}\ of\ \frac{3}{4}\times\frac{1}{2}\div\frac{2}{3}\)

Step 1: Find \(\frac{1}{2}\) of \(\frac{3}{4}\):
\(\frac{1}{2} \times \frac{3}{4} = \frac{3}{8}\)
Step 2: Multiply by \(\frac{1}{2}\):
\(\frac{3}{8} \times \frac{1}{2} = \frac{3}{16}\)
Step 3: Divide by \(\frac{2}{3}\):
\(\frac{3}{16} \div \frac{2}{3} = \frac{3}{16} \times \frac{3}{2} = \frac{9}{32}\)
Answer: \(\frac{9}{32}\)


Q6: A bought \(3\frac{3}{4}\) kg of wheat and \(2\frac{1}{2}\) kg of rice. Find the total weight of wheat and rice bought by A.

Step 1: Convert the mixed fractions to improper fractions:
\(3\frac{3}{4} = \frac{12+3}{4} = \frac{15}{4}\)
\(2\frac{1}{2} = \frac{4+1}{2} = \frac{5}{2}\)
Step 2: To add the fractions, we need a common denominator. The least common denominator (LCD) of 4 and 2 is 4.
Convert \(\frac{5}{2}\) to an equivalent fraction with denominator 4:
\[ \frac{5}{2} = \frac{5 \times 2}{2 \times 2} = \frac{10}{4} \]Step 3: Now add the two fractions:
\[ \frac{15}{4} + \frac{10}{4} = \frac{15+10}{4} = \frac{25}{4} \]Step 4: Convert the improper fraction \(\frac{25}{4}\) back to a mixed fraction:
\[ \frac{25}{4} = 6 \frac{1}{4} \]Answer: The total weight of wheat and rice bought by A is \(6\frac{1}{4}\) kg.


Q7: Which is greater, \(\frac{3}{5}\) or \(\frac{7}{10}\) and by how much?

Step 1: To compare \(\frac{3}{5}\) and \(\frac{7}{10}\), we need a common denominator. The least common denominator (LCD) of 5 and 10 is 10.
Step 2: Convert \(\frac{3}{5}\) to an equivalent fraction with denominator 10:
\[ \frac{3}{5} = \frac{3 \times 2}{5 \times 2} = \frac{6}{10} \]Step 3: Now compare the two fractions: \(\frac{6}{10}\) and \(\frac{7}{10}\). Since the denominators are the same, we can directly compare the numerators.
Clearly, \(\frac{7}{10} > \frac{6}{10}\).Step 4: To find by how much \(\frac{7}{10}\) is greater than \(\frac{3}{5}\), subtract \(\frac{6}{10}\) from \(\frac{7}{10}\):
\[ \frac{7}{10} – \frac{6}{10} = \frac{1}{10} \]Answer: \(\frac{7}{10}\) is greater than \(\frac{3}{5}\) by \(\frac{1}{10}\).


Q8: What number should be added to \(8\frac{2}{3}\) to get \(12\frac{5}{6}\)?

Step 1: To solve this, we need to subtract \(8\frac{2}{3}\) from \(12\frac{5}{6}\). The number to be added to \(8\frac{2}{3}\) is the difference between these two mixed fractions.
Step 2: Convert both mixed fractions to improper fractions.
For \(8\frac{2}{3}\): \[ 8\frac{2}{3} = \frac{8 \times 3 + 2}{3} = \frac{24 + 2}{3} = \frac{26}{3} \]For \(12\frac{5}{6}\): \[ 12\frac{5}{6} = \frac{12 \times 6 + 5}{6} = \frac{72 + 5}{6} = \frac{77}{6} \]Step 3: Subtract \(\frac{26}{3}\) from \(\frac{77}{6}\). To do this, we need a common denominator. The least common denominator (LCD) of 3 and 6 is 6.
Convert \(\frac{26}{3}\) to a fraction with denominator 6: \[ \frac{26}{3} = \frac{26 \times 2}{3 \times 2} = \frac{52}{6} \]Step 4: Now subtract the fractions: \[ \frac{77}{6} – \frac{52}{6} = \frac{77 – 52}{6} = \frac{25}{6} \]Step 5: Convert the improper fraction \(\frac{25}{6}\) back to a mixed fraction: \[ \frac{25}{6} = 4\frac{1}{6} \]Answer: The number that should be added to \(8\frac{2}{3}\) to get \(12\frac{5}{6}\) is \(4\frac{1}{6}\).


Q9: What should be subtracted from \(8\frac{3}{4}\) to get \(2\frac{2}{3}\)?

Step 1: To find what should be subtracted, we need to subtract \(2\frac{2}{3}\) from \(8\frac{3}{4}\). \[ \text{What to subtract} = 8\frac{3}{4} – 2\frac{2}{3} \]Step 2: Convert the mixed fractions to improper fractions.For \(8\frac{3}{4}\): \[ 8\frac{3}{4} = \frac{8 \times 4 + 3}{4} = \frac{32 + 3}{4} = \frac{35}{4} \]For \(2\frac{2}{3}\): \[ 2\frac{2}{3} = \frac{2 \times 3 + 2}{3} = \frac{6 + 2}{3} = \frac{8}{3} \]Step 3: Subtract the fractions: \[ \frac{35}{4} – \frac{8}{3} \] To subtract these fractions, we need to find a common denominator. The least common denominator (LCD) of 4 and 3 is 12.Convert both fractions: \[ \frac{35}{4} = \frac{35 \times 3}{4 \times 3} = \frac{105}{12} \] \[ \frac{8}{3} = \frac{8 \times 4}{3 \times 4} = \frac{32}{12} \]Now subtract the fractions: \[ \frac{105}{12} – \frac{32}{12} = \frac{105 – 32}{12} = \frac{73}{12} \]Step 4: Convert the improper fraction \(\frac{73}{12}\) back to a mixed fraction: \[ \frac{73}{12} = 6\frac{1}{12} \]Answer: The number that should be subtracted from \(8\frac{3}{4}\) to get \(2\frac{2}{3}\) is \(6\frac{1}{12}\).


Q10: A rectangular field is \(16\frac{1}{2}\) m long and \(12\frac{2}{5}\) m wide. Find the perimeter of the field.

Step 1: The perimeter \(P\) of a rectangle is given by the formula: \[ P = 2 \times ( \text{length} + \text{width} ) \]Step 2: Convert the mixed fractions for length and width into improper fractions.For the length \(16\frac{1}{2}\): \[ 16\frac{1}{2} = \frac{16 \times 2 + 1}{2} = \frac{32 + 1}{2} = \frac{33}{2} \]For the width \(12\frac{2}{5}\): \[ 12\frac{2}{5} = \frac{12 \times 5 + 2}{5} = \frac{60 + 2}{5} = \frac{62}{5} \]Step 3: Add the length and the width: \[ \frac{33}{2} + \frac{62}{5} \] To add these fractions, we need to find a common denominator. The least common denominator (LCD) of 2 and 5 is 10.Convert both fractions: \[ \frac{33}{2} = \frac{33 \times 5}{2 \times 5} = \frac{165}{10} \] \[ \frac{62}{5} = \frac{62 \times 2}{5 \times 2} = \frac{124}{10} \]Now add the fractions: \[ \frac{165}{10} + \frac{124}{10} = \frac{165 + 124}{10} = \frac{289}{10} \]Step 4: Multiply the sum by 2 to find the perimeter: \[ P = 2 \times \frac{289}{10} = \frac{578}{10} = 57\frac{8}{10} = 57\frac{4}{5} \]Answer: The perimeter of the field is \(57\frac{4}{5}\) meters.


Q11: Sugar costs ₹ \(37\frac{1}{2}\) per kg. Find the cost of \(8\frac{3}{4}\) kg sugar.

Step 1: Convert the mixed numbers to improper fractions.Cost per kg: \[ ₹37\frac{1}{2} = \frac{75}{2} \]Weight of sugar: \[ 8\frac{3}{4} = \frac{35}{4} \]Step 2: Multiply the two improper fractions: \[ \text{Total cost} = \frac{75}{2} \times \frac{35}{4} \]Multiply numerators and denominators: \[ = \frac{75 \times 35}{2 \times 4} = \frac{2625}{8} \]Step 3: Convert the improper fraction to a mixed number: \[ \frac{2625}{8} = 328 \frac{1}{8} \]Answer: ₹ \(328 \frac{1}{8}\) or ₹ 328.125


Q12: A cycle runs \(31\frac{1}{4}\) km consuming 1 litte of petrol. How much distance will it run consuming \(1\frac{3}{5}\) litre of petrol?

Step 1: Convert the mixed numbers to improper fractions.Distance per litre: \[ 31\frac{1}{4} = \frac{125}{4} \]Petrol used: \[ 1\frac{3}{5} = \frac{8}{5} \]Step 2: Multiply the two values to get total distance: \[ \text{Total distance} = \frac{125}{4} \times \frac{8}{5} \]Multiply numerators and denominators: \[ = \frac{125 \times 8}{4 \times 5} = \frac{1000}{20} \]Simplify: \[ = 50 \text{ km} \]Answer: 50 km


Q13: A rectangular park has length = \(23\frac{2}{5}\) m and breadth = \(16\frac{2}{3}\) m. Find the area of the park.

Step 1: Convert mixed numbers to improper fractions.Length: \[ 23\frac{2}{5} = \frac{117}{5} \]Breadth: \[ 16\frac{2}{3} = \frac{50}{3} \]Step 2: Use the formula for area of a rectangle: \[ \text{Area} = \text{Length} \times \text{Breadth} \]Substitute the values: \[ \text{Area} = \frac{117}{5} \times \frac{50}{3} \]Step 3: Multiply numerators and denominators: \[ = \frac{117 \times 50}{5 \times 3} = \frac{5850}{15} \]Step 4: Simplify the fraction: \[ = 390 \text{ m}^2 \]Answer: 390 m²


Q14: Each of 40 identical boxes weighs \(4\frac{4}{5}\) kg. Find the total weight of all the boxes.

Step 1: Convert the mixed number to an improper fraction. \[ 4\frac{4}{5} = \frac{24}{5} \]Step 2: Multiply the weight of one box by the total number of boxes. \[ \text{Total weight} = 40 \times \frac{24}{5} \]Step 3: Multiply: \[ = \frac{40 \times 24}{5} = \frac{960}{5} \]Step 4: Simplify: \[ = 192 \text{ kg} \]Answer: 192 kg


Q15: Out of 24 kg of wheat, \(\frac{5}{6}\)th of wheat is consumed. Find how much wheat is still left?

Step 1: Total wheat available = 24 kgStep 2: Fraction of wheat consumed = \(\frac{5}{6}\)Step 3: Find the quantity consumed:
\[ \frac{5}{6} \times 24 = \frac{120}{6} = 20 \text{ kg} \]Step 4: Subtract consumed wheat from total:
\[ \text{Wheat left} = 24 – 20 = 4 \text{ kg} \]Answer: 4 kg


Q16: A rod of \(2\frac{2}{5}\) metre is divided into five equal parts. Find the length of each part so obtained.

Step 1: Total length of the rod = \(2\frac{2}{5}\) metres Convert to improper fraction: \[ 2\frac{2}{5} = \frac{(2 \times 5) + 2}{5} = \frac{10 + 2}{5} = \frac{12}{5} \]Step 2: Divide the rod into 5 equal parts: \[ \text{Length of each part} = \frac{12}{5} \div 5 = \frac{12}{5} \times \frac{1}{5} = \frac{12}{25} \]Step 3: Convert to decimal or mixed fraction (optional): \[ \frac{12}{25} = 0.48 \text{ metre} \]Answer: \(\frac{12}{25}\) metre or 0.48 metre


Q17: 1f A = \(3\frac{3}{8}\) and B = \(6\frac{5}{8}\), find:

i. A ÷ B

Step 1: Convert A and B to improper fractions A = \(3\frac{3}{8} = \frac{(3×8)+3}{8} = \frac{24+3}{8} = \frac{27}{8}\) B = \(6\frac{5}{8} = \frac{(6×8)+5}{8} = \frac{48+5}{8} = \frac{53}{8}\)Step 2: Calculate A ÷ B \[ \frac{27}{8} \div \frac{53}{8} = \frac{27}{8} \times \frac{8}{53} = \frac{216}{424} \] Now reduce the fraction: \[ \frac{216}{424} = \frac{54}{106} = \frac{27}{53} \]Answer: A ÷ B = \(\frac{27}{53}\)

ii. B ÷ A

Step 1: Calculate B ÷ A \[ \frac{53}{8} \div \frac{27}{8} = \frac{53}{8} \times \frac{8}{27} = \frac{424}{216} \] Now reduce the fraction: \[ \frac{424}{216} = \frac{106}{54} = \frac{53}{27} \]Answer: B ÷ A = \(\frac{53}{27}\) or \(1\frac{26}{27}\)


Q18: Cost of \(3\frac{5}{7}\) litres of oil is ₹ \(83\frac{1}{2}\). Find the cost of one litre oil.

Step 1: Convert the mixed numbers into improper fractions.Cost = ₹ \(83\frac{1}{2} = \frac{(83×2)+1}{2} = \frac{166+1}{2} = \frac{167}{2}\) Quantity = \(3\frac{5}{7} = \frac{(3×7)+5}{7} = \frac{21+5}{7} = \frac{26}{7}\)Step 2: To find the cost of 1 litre oil, divide total cost by total litres: \[ \text{Cost of 1 litre} = \frac{167}{2} \div \frac{26}{7} = \frac{167}{2} \times \frac{7}{26} \]Step 3: Multiply the numerators and denominators: \[ = \frac{167×7}{2×26} = \frac{1169}{52} \]Step 4: Convert the improper fraction into a mixed number: \[ 1169 ÷ 52 = 22 \text{ remainder } 25 \] \[ \Rightarrow \frac{1169}{52} = 22\frac{25}{52} \]Answer: ₹ \(22\frac{25}{52}\) per litre


Q19: The product of two numbers is \(20\frac{5}{7}\). If one of these numbers is \(6\frac{2}{3}\), find the other.

Step 1: Convert the mixed numbers into improper fractions. \[ 20\frac{5}{7} = \frac{(20 \times 7) + 5}{7} = \frac{140 + 5}{7} = \frac{145}{7} \] \[ 6\frac{2}{3} = \frac{(6 \times 3) + 2}{3} = \frac{18 + 2}{3} = \frac{20}{3} \]Step 2: Let the other number be \(x\). Then: \[ x \times \frac{20}{3} = \frac{145}{7} \]Step 3: Solve for \(x\) by dividing both sides by \(\frac{20}{3}\): \[ x = \frac{145}{7} \div \frac{20}{3} = \frac{145}{7} \times \frac{3}{20} \]Step 4: Multiply the fractions: \[ x = \frac{145 \times 3}{7 \times 20} = \frac{435}{140} \]Step 5: Simplify the fraction: \[ \frac{435}{140} = \frac{87}{28} \quad \text{(Divide numerator and denominator by 5)} \]Step 6: Convert to mixed number: \[ 87 ÷ 28 = 3 \text{ remainder } 3 \Rightarrow \frac{87}{28} = 3\frac{3}{28} \]Answer: \(3\frac{3}{28}\)


Q20: By what number should \(5\frac{5}{6}\) be multiplied to get \(3\frac{1}{3}\)?

Step 1: Convert the mixed numbers into improper fractions. \[ 5\frac{5}{6} = \frac{(5 \times 6) + 5}{6} = \frac{30 + 5}{6} = \frac{35}{6} \] \[ 3\frac{1}{3} = \frac{(3 \times 3) + 1}{3} = \frac{9 + 1}{3} = \frac{10}{3} \]Step 2: Let the required number be \(x\). Then, \[ \frac{35}{6} \times x = \frac{10}{3} \]Step 3: Solve for \(x\) by dividing both sides by \(\frac{35}{6}\): \[ x = \frac{10}{3} \div \frac{35}{6} = \frac{10}{3} \times \frac{6}{35} \]Step 4: Multiply the numerators and denominators: \[ x = \frac{10 \times 6}{3 \times 35} = \frac{60}{105} \]Step 5: Simplify the fraction: \[ \frac{60}{105} = \frac{12}{21} = \frac{4}{7} \quad \text{(Divide by 3, then by 3 again)} \]Answer: \(\frac{4}{7}\)


previous
next

Share the Post:

Leave a Comment

Your email address will not be published. Required fields are marked *

Related Posts​

  • Type casting in Java
    The process of converting the value of one data type to another data type is known as typecasting.
  • Identities
    Step by Step solutions of Test Yourself Concise Mathematics ICSE Class-8 Maths chapter 12- Identities by Selina is provided.

Join Our Newsletter

Name
Email
The form has been submitted successfully!
There has been some error while submitting the form. Please verify all form fields again.

Scroll to Top