Exercise: 4-D
Q1: Find the sum of:
i. \(\frac{2}{7} + \frac{3}{7}\)
Step 1: Denominators are same, so add numerators.
\[
\frac{2}{7} + \frac{3}{7} = \frac{2+3}{7} = \frac{5}{7}
\]
Answer: \(\frac{5}{7}\)
ii. \(\frac{5}{8} + \frac{1}{8}\)
Step 1: Denominators are same, so add numerators.
\[
\frac{5}{8} + \frac{1}{8} = \frac{5+1}{8} = \frac{6}{8}
\]
Step 2: Simplify the fraction.
\[
\frac{6}{8} = \frac{3}{4}
\]
Answer: \(\frac{3}{4}\)
iii. \(\frac{7}{9} + \frac{4}{9}\)
Step 1: Denominators are same, so add numerators.
\[
\frac{7}{9} + \frac{4}{9} = \frac{7+4}{9} = \frac{11}{9}
\]
Step 2: Convert improper fraction to mixed number.
\[
\frac{11}{9} = 1 \frac{2}{9}
\]
Answer: \(1 \frac{2}{9}\)
iv. \(1\frac{5}{6} + \frac{1}{6}\)
Step 1: Convert mixed number to improper fraction.
\[
1 \frac{5}{6} = \frac{6 \times 1 + 5}{6} = \frac{11}{6}
\]
Step 2: Add fractions with same denominator.
\[
\frac{11}{6} + \frac{1}{6} = \frac{11+1}{6} = \frac{12}{6} = 2
\]
Answer: 2
Q2: Find the sum of:
i. \(\frac{5}{14} + \frac{3}{14} + \frac{1}{14}\)
Step 1: Denominators are same, so add numerators.
\[
\frac{5}{14} + \frac{3}{14} + \frac{1}{14} = \frac{5 + 3 + 1}{14} = \frac{9}{14}
\]
Answer: \(\frac{9}{14}\)
ii. \(\frac{7}{12} + \frac{5}{12} + \frac{11}{12}\)
Step 1: Denominators are same, so add numerators.
\[
\frac{7}{12} + \frac{5}{12} + \frac{11}{12} = \frac{7 + 5 + 11}{12} = \frac{23}{12}
\]
Step 2: Convert improper fraction to mixed number.
\[
\frac{23}{12} = 1 \frac{11}{12}
\]
Answer: \(1 \frac{11}{12}\)
iii. \(1 \frac{7}{8} + \frac{3}{8} + 1 \frac{5}{8}\)
Step 1: Convert mixed numbers to improper fractions.
\[
1 \frac{7}{8} = \frac{8 \times 1 + 7}{8} = \frac{15}{8} \\
1 \frac{5}{8} = \frac{8 \times 1 + 5}{8} = \frac{13}{8}
\]
Step 2: Add all fractions (denominators are same).
\[
\frac{15}{8} + \frac{3}{8} + \frac{13}{8} = \frac{15 + 3 + 13}{8} = \frac{31}{8}
\]
Step 3: Convert improper fraction to mixed number.
\[
\frac{31}{8} = 3 \frac{7}{8}
\]
Answer: \(3 \frac{7}{8}\)
Q3: Find the sum of:
i. \(\frac{4}{9} + \frac{5}{6}\)
Step 1: Find the LCM of denominators 9 and 6.
LCM (9,6) = 18
Step 2: Convert fractions to equivalent fractions with denominator 18.
\[
\frac{4}{9} = \frac{4 \times 2}{9 \times 2} = \frac{8}{18} \\
\frac{5}{6} = \frac{5 \times 3}{6 \times 3} = \frac{15}{18}
\]
Step 3: Add the fractions.
\[
\frac{8}{18} + \frac{15}{18} = \frac{8 + 15}{18} = \frac{23}{18}
\]
Step 4: Convert improper fraction to mixed number.
\[
\frac{23}{18} = 1 \frac{5}{18}
\]
Answer: \(1 \frac{5}{18}\)
ii. \(\frac{5}{12} + \frac{9}{16}\)
Step 1: Find the LCM of denominators 12 and 16.
LCM (12,16) = 48
Step 2: Convert fractions to equivalent fractions with denominator 48.
\[
\frac{5}{12} = \frac{5 \times 4}{12 \times 4} = \frac{20}{48} \\
\frac{9}{16} = \frac{9 \times 3}{16 \times 3} = \frac{27}{48}
\]
Step 3: Add the fractions.
\[
\frac{20}{48} + \frac{27}{48} = \frac{20 + 27}{48} = \frac{47}{48}
\]
Answer: \(\frac{47}{48}\)
iii. \(\frac{7}{12} + \frac{13}{18}\)
Step 1: Find the LCM of denominators 12 and 18.
LCM (12,18) = 36
Step 2: Convert fractions to equivalent fractions with denominator 36.
\[
\frac{7}{12} = \frac{7 \times 3}{12 \times 3} = \frac{21}{36} \\
\frac{13}{18} = \frac{13 \times 2}{18 \times 2} = \frac{26}{36}
\]
Step 3: Add the fractions.
\[
\frac{21}{36} + \frac{26}{36} = \frac{21 + 26}{36} = \frac{47}{36}
\]
Step 4: Convert improper fraction to mixed number.
\[
\frac{47}{36} = 1 \frac{11}{36}
\]
Answer: \(1 \frac{11}{36}\)
Q4: Find the sum of:
i. \(\frac{3}{10} + \frac{8}{15} + \frac{7}{20}\)
Step 1: Find the LCM of denominators 10, 15, and 20.
LCM (10,15,20) = 60
Step 2: Convert each fraction to have denominator 60.
\[
\frac{3}{10} = \frac{3 \times 6}{10 \times 6} = \frac{18}{60} \\
\frac{8}{15} = \frac{8 \times 4}{15 \times 4} = \frac{32}{60} \\
\frac{7}{20} = \frac{7 \times 3}{20 \times 3} = \frac{21}{60}
\]
Step 3: Add the fractions.
\[
\frac{18}{60} + \frac{32}{60} + \frac{21}{60} = \frac{18 + 32 + 21}{60} = \frac{71}{60}
\]
Step 4: Convert improper fraction to mixed number.
\[
\frac{71}{60} = 1 \frac{11}{60}
\]
Answer: \(1 \frac{11}{60}\)
ii. \(\frac{7}{8} + \frac{9}{16} + \frac{17}{24}\)
Step 1: Find the LCM of denominators 8, 16, and 24.
LCM (8,16,24) = 48
Step 2: Convert each fraction to have denominator 48.
\[
\frac{7}{8} = \frac{7 \times 6}{8 \times 6} = \frac{42}{48} \\
\frac{9}{16} = \frac{9 \times 3}{16 \times 3} = \frac{27}{48} \\
\frac{17}{24} = \frac{17 \times 2}{24 \times 2} = \frac{34}{48}
\]
Step 3: Add the fractions.
\[
\frac{42}{48} + \frac{27}{48} + \frac{34}{48} = \frac{42 + 27 + 34}{48} = \frac{103}{48}
\]
Step 4: Convert improper fraction to mixed number.
\[
\frac{103}{48} = 2 \frac{7}{48}
\]
Answer: \(2 \frac{7}{48}\)
iii. \(\frac{5}{6} + \frac{8}{9} + \frac{11}{18} + \frac{13}{27}\)
Step 1: Find the LCM of denominators 6, 9, 18, and 27.
LCM (6,9,18,27) = 54
Step 2: Convert each fraction to have denominator 54.
\[
\frac{5}{6} = \frac{5 \times 9}{6 \times 9} = \frac{45}{54} \\
\frac{8}{9} = \frac{8 \times 6}{9 \times 6} = \frac{48}{54} \\
\frac{11}{18} = \frac{11 \times 3}{18 \times 3} = \frac{33}{54} \\
\frac{13}{27} = \frac{13 \times 2}{27 \times 2} = \frac{26}{54}
\]
Step 3: Add the fractions.
\[
\frac{45}{54} + \frac{48}{54} + \frac{33}{54} + \frac{26}{54} \\
= \frac{45 + 48 + 33 + 26}{54} = \frac{152}{54}
\]
Step 4: Simplify the fraction.
\[
\frac{152}{54} = \frac{76}{27}
\]
Step 5: Convert improper fraction to mixed number.
\[
\frac{76}{27} = 2 \frac{22}{27}
\]
Answer: \(2 \frac{22}{27}\)
Q5: Find the sum of:
i. \(4\frac{1}{6} + 2\frac{5}{8} + 3\frac{7}{12}\)
Step 1: Convert mixed fractions to improper fractions.
\[
4\frac{1}{6} = \frac{4 \times 6 + 1}{6} = \frac{25}{6} \\
2\frac{5}{8} = \frac{2 \times 8 + 5}{8} = \frac{21}{8} \\
3\frac{7}{12} = \frac{3 \times 12 + 7}{12} = \frac{43}{12}
\]
Step 2: Find LCM of denominators 6, 8, and 12.
LCM (6,8,12) = 24
Step 3: Convert fractions to denominator 24.
\[
\frac{25}{6} = \frac{25 \times 4}{6 \times 4} = \frac{100}{24} \\
\frac{21}{8} = \frac{21 \times 3}{8 \times 3} = \frac{63}{24} \\
\frac{43}{12} = \frac{43 \times 2}{12 \times 2} = \frac{86}{24}
\]
Step 4: Add the fractions.
\[
\frac{100}{24} + \frac{63}{24} + \frac{86}{24} = \frac{249}{24}
\]
Step 5: Convert improper fraction to mixed number.
\[
\frac{249}{24} = 10 \frac{9}{24} = 10 \frac{3}{8}
\]
Answer: \(10 \frac{3}{8}\)
ii. \(1\frac{1}{2} + 2\frac{2}{3} + 3\frac{3}{4} + 4\frac{4}{5}\)
Step 1: Convert mixed fractions to improper fractions.
\[
1\frac{1}{2} = \frac{1 \times 2 + 1}{2} = \frac{3}{2} \\
2\frac{2}{3} = \frac{2 \times 3 + 2}{3} = \frac{8}{3} \\
3\frac{3}{4} = \frac{3 \times 4 + 3}{4} = \frac{15}{4} \\
4\frac{4}{5} = \frac{4 \times 5 + 4}{5} = \frac{24}{5}
\]
Step 2: Find LCM of denominators 2, 3, 4, and 5.
LCM (2,3,4,5) = 60
Step 3: Convert fractions to denominator 60.
\[
\frac{3}{2} = \frac{3 \times 30}{2 \times 30} = \frac{90}{60} \\
\frac{8}{3} = \frac{8 \times 20}{3 \times 20} = \frac{160}{60} \\
\frac{15}{4} = \frac{15 \times 15}{4 \times 15} = \frac{225}{60} \\
\frac{24}{5} = \frac{24 \times 12}{5 \times 12} = \frac{288}{60}
\]
Step 4: Add the fractions.
\[
\frac{90}{60} + \frac{160}{60} + \frac{225}{60} + \frac{288}{60} = \frac{763}{60}
\]
Step 5: Convert improper fraction to mixed number.
\[
\frac{763}{60} = 12 \frac{43}{60}
\]
Answer: \(12 \frac{43}{60}\)
iii. \(3\frac{1}{3} + 2\frac{2}{9} + 4\frac{1}{2} + 1\frac{13}{18}\)
Step 1: Convert mixed fractions to improper fractions.
\[
3\frac{1}{3} = \frac{3 \times 3 + 1}{3} = \frac{10}{3} \\
2\frac{2}{9} = \frac{2 \times 9 + 2}{9} = \frac{20}{9} \\
4\frac{1}{2} = \frac{4 \times 2 + 1}{2} = \frac{9}{2} \\
1\frac{13}{18} = \frac{1 \times 18 + 13}{18} = \frac{31}{18}
\]
Step 2: Find LCM of denominators 3, 9, 2, and 18.
LCM (3,9,2,18) = 18
Step 3: Convert fractions to denominator 18.
\[
\frac{10}{3} = \frac{10 \times 6}{3 \times 6} = \frac{60}{18} \\
\frac{20}{9} = \frac{20 \times 2}{9 \times 2} = \frac{40}{18} \\
\frac{9}{2} = \frac{9 \times 9}{2 \times 9} = \frac{81}{18} \\
\frac{31}{18} = \frac{31}{18}
\]
Step 4: Add the fractions.
\[
\frac{60}{18} + \frac{40}{18} + \frac{81}{18} + \frac{31}{18} = \frac{212}{18}
\]
Step 5: Simplify the fraction.
\[
\frac{212}{18} = \frac{106}{9}
\]
Step 6: Convert improper fraction to mixed number.
\[
\frac{106}{9} = 11 \frac{7}{9}
\]
Answer: \(11 \frac{7}{9}\)
Q6: Find the difference:
i. \(\frac{9}{11} – \frac{5}{11}\)
Step 1: Since denominators are the same, subtract numerators.
\[
\frac{9}{11} – \frac{5}{11} = \frac{9 – 5}{11} = \frac{4}{11}
\]
Answer: \(\frac{4}{11}\)
ii. \(8\frac{5}{7} – \frac{6}{7}\)
Step 1: Convert mixed fraction to improper fraction.
\[
8\frac{5}{7} = \frac{8 \times 7 + 5}{7} = \frac{61}{7}
\]
Step 2: Subtract the fractions (denominator same).
\[
\frac{61}{7} – \frac{6}{7} = \frac{61 – 6}{7} = \frac{55}{7}
\]
Step 3: Convert improper fraction to mixed number.
\[
\frac{55}{7} = 7 \frac{6}{7}
\]
Answer: \(7 \frac{6}{7}\)
iii. \(3\frac{3}{8} – 1\frac{7}{8}\)
Step 1: Convert mixed fractions to improper fractions.
\[
3\frac{3}{8} = \frac{3 \times 8 + 3}{8} = \frac{27}{8} \\
1\frac{7}{8} = \frac{1 \times 8 + 7}{8} = \frac{15}{8}
\]
Step 2: Subtract the fractions (denominators are same).
\[
\frac{27}{8} – \frac{15}{8} = \frac{27 – 15}{8} = \frac{12}{8}
\]
Step 3: Simplify the fraction.
\[
\frac{12}{8} = \frac{3}{2} = 1 \frac{1}{2}
\]
Answer: \(1 \frac{1}{2}\)
iv. \(\frac{7}{4} – \frac{3}{4}\)
Step 1: Subtract the numerators as denominators are same.
\[
\frac{7}{4} – \frac{3}{4} = \frac{7 – 3}{4} = \frac{4}{4} = 1
\]
Answer: \(1\)
Q7: Find the difference:
i. \(\frac{7}{15} – \frac{9}{20}\)
Step 1: Find LCM of 15 and 20.
LCM(15, 20) = 60
\[
\frac{7}{15} = \frac{28}{60},\quad \frac{9}{20} = \frac{27}{60}
\]
Step 2: Subtract the numerators.
\[
\frac{28}{60} – \frac{27}{60} = \frac{1}{60}
\]
Answer: \(\frac{1}{60}\)
ii. \(4\frac{1}{7} – 2\frac{1}{14}\)
Step 1: Convert to improper fractions.
\[
4\frac{1}{7} = \frac{29}{7},\quad 2\frac{1}{14} = \frac{29}{14}
\]
Step 2: Find LCM of 7 and 14 = 14
\[
\frac{29}{7} = \frac{58}{14},\quad \frac{29}{14} = \frac{29}{14} \\
\frac{58}{14} – \frac{29}{14} = \frac{29}{14}
\]
Step 3: Convert to mixed number.
\[
\frac{29}{14} = 2 \frac{1}{14}
\]
Answer: \(2 \frac{1}{14}\)
iii. \(1\frac{7}{8} – \frac{5}{12}\)
Step 1: Convert mixed to improper fraction.
\[
1\frac{7}{8} = \frac{15}{8}
\]
Step 2: Find LCM of 8 and 12 = 24
\[
\frac{15}{8} = \frac{45}{24},\quad \frac{5}{12} = \frac{10}{24}
\]
Step 3: Subtract:
\[
\frac{45}{24} – \frac{10}{24} = \frac{35}{24}
\]
Step 4: Convert to mixed number.
\[
\frac{35}{24} = 1 \frac{11}{24}
\]
Answer: \(1 \frac{11}{24}\)
iv. \(5 – 2\frac{3}{4}\)
Step 1: Convert mixed number to improper fraction.
\[
2\frac{3}{4} = \frac{11}{4} \\
5 = \frac{20}{4}
\]
Step 2: Subtract:
\[
\frac{20}{4} – \frac{11}{4} = \frac{9}{4} = 2 \frac{1}{4}
\]
Answer: \(2 \frac{1}{4}\)
Q8: Find the difference:
i. \(5\frac{1}{8} – 4\frac{1}{12}\)
Step 1: Convert to improper fractions.
\[
5\frac{1}{8} = \frac{41}{8},\quad 4\frac{1}{12} = \frac{49}{12}
\]
Step 2: Find LCM of 8 and 12 = 24
\[
\frac{41}{8} = \frac{123}{24},\quad \frac{49}{12} = \frac{98}{24}
\]
Step 3: Subtract:
\[
\frac{123}{24} – \frac{98}{24} = \frac{25}{24} = 1 \frac{1}{24}
\]
Answer: \(1 \frac{1}{24}\)
ii. \(6\frac{1}{6} – 3\frac{7}{10}\)
Step 1: Convert to improper fractions.
\[
6\frac{1}{6} = \frac{37}{6},\quad 3\frac{7}{10} = \frac{37}{10}
\]
Step 2: Find LCM of 6 and 10 = 30
\[
\frac{37}{6} = \frac{185}{30},\quad \frac{37}{10} = \frac{111}{30}
\]
Step 3: Subtract:
\[
\frac{185}{30} – \frac{111}{30} = \frac{74}{30}
\]
Step 4: Simplify:
\[
\frac{74}{30} = \frac{37}{15} = 2 \frac{7}{15}
\]
Answer: \(2 \frac{7}{15}\)
iii. \(12 – 6\frac{5}{8}\)
Step 1: Convert mixed number to improper fraction.
\[
6\frac{5}{8} = \frac{53}{8},\quad 12 = \frac{96}{8}
\]
Step 2: Subtract:
\[
\frac{96}{8} – \frac{53}{8} = \frac{43}{8} = 5 \frac{3}{8}
\]
Answer: \(5 \frac{3}{8}\)
Q9: Simplify: \(\frac{4}{9} – \frac{5}{12} + \frac{1}{4}\)
Step 1: Find the LCM of the denominators 9, 12, and 4.
LCM of 9, 12, and 4 = 36
Step 2: Convert all fractions to have a denominator of 36:
\[
\frac{4}{9} = \frac{4 \times 4}{9 \times 4} = \frac{16}{36} \\
\frac{5}{12} = \frac{5 \times 3}{12 \times 3} = \frac{15}{36} \\
\frac{1}{4} = \frac{1 \times 9}{4 \times 9} = \frac{9}{36}
\]Step 3: Now perform the operations:
\[
\frac{16}{36} – \frac{15}{36} + \frac{9}{36} = \frac{(16 – 15 + 9)}{36} = \frac{10}{36}
\]Step 4: Simplify the result:
\[
\frac{10}{36} = \frac{5}{18}
\]Answer: \(\frac{5}{18}\)
Q10: Simplify: \(6\frac{2}{3} + 4\frac{1}{6} – 2\frac{2}{9}\)
Step 1: Convert all mixed fractions into improper fractions:
\[
6\frac{2}{3} = \frac{20}{3} \\
4\frac{1}{6} = \frac{25}{6} \\
2\frac{2}{9} = \frac{20}{9}
\]Step 2: Find LCM of denominators: 3, 6, and 9.
LCM = 18
Step 3: Convert each fraction to have denominator 18:
\[
\frac{20}{3} = \frac{120}{18} \\
\frac{25}{6} = \frac{75}{18} \\
\frac{20}{9} = \frac{40}{18}
\]Step 4: Now perform the operations:
\[
\frac{120}{18} + \frac{75}{18} – \frac{40}{18} = \frac{(120 + 75 – 40)}{18} = \frac{155}{18}
\]Step 5: Convert to mixed fraction:
\[
\frac{155}{18} = 8\frac{11}{18}
\]Answer: \(8\frac{11}{18}\)
Q11: Simplify: \(9 – 4\frac{1}{2} – 2\frac{1}{5}\)
Step 1: Convert mixed fractions into improper fractions:
\[
4\frac{1}{2} = \frac{9}{2} \\
2\frac{1}{5} = \frac{11}{5}
\]
Step 2: Convert 9 into a fraction with LCM of 2 and 5 = 10.
\[
9 = \frac{90}{10},\quad \frac{9}{2} = \frac{45}{10},\quad \frac{11}{5} = \frac{22}{10}
\]Step 3: Perform the subtraction:
\[
\frac{90}{10} – \frac{45}{10} – \frac{22}{10} = \frac{(90 – 45 – 22)}{10} = \frac{23}{10}
\]Step 4: Convert to mixed number:
\[
\frac{23}{10} = 2\frac{3}{10}
\]Answer: \(2\frac{3}{10}\)
Q12: Simplify: \(10\frac{3}{4} – 5\frac{1}{8} – 4\frac{5}{12}\)
Step 1: Convert all mixed numbers into improper fractions:
\[
10\frac{3}{4} = \frac{43}{4} \\
5\frac{1}{8} = \frac{41}{8} \\
4\frac{5}{12} = \frac{53}{12}
\]
Step 2: Find LCM of denominators 4, 8, and 12.
LCM (4, 8, 12) = 24
Convert all fractions to have denominator 24:\[
\frac{43}{4} = \frac{258}{24},\quad \frac{41}{8} = \frac{123}{24},\quad \frac{53}{12} = \frac{106}{24}
\]Step 3: Perform the subtraction:\[
\frac{258}{24} – \frac{123}{24} – \frac{106}{24} = \frac{(258 – 123 – 106)}{24} = \frac{29}{24}
\]Step 4: Convert to mixed number:\[
\frac{29}{24} = 1\frac{5}{24}
\]Answer: \(1\frac{5}{24}\)
Q13: Simplify: \(6\frac{4}{5} – 3\frac{4}{15} + 4\frac{3}{10}\)
Step 1: Convert all mixed numbers into improper fractions:
\[6\frac{4}{5} = \frac{34}{5} \\
3\frac{4}{15} = \frac{49}{15} \\
4\frac{3}{10} = \frac{43}{10}
\]Step 2: Find LCM of denominators 5, 15, and 10.
LCM (5, 15, 10) = 30
Convert all fractions to have denominator 30:\[
\frac{34}{5} = \frac{204}{30},\quad \frac{49}{15} = \frac{98}{30},\quad \frac{43}{10} = \frac{129}{30}
\]Step 3: Perform the operations:\[
\frac{204}{30} – \frac{98}{30} + \frac{129}{30} = \frac{(204 – 98 + 129)}{30} = \frac{235}{30}
\]Step 4: Simplify the result:\[
\frac{235}{30} = 7\frac{25}{30} = 7\frac{5}{6}
\]Answer: \(7\frac{5}{6}\)
Q14: Simplify: \(4\frac{5}{12}+3\frac{11}{18}-2\frac{7}{24}\)
Step 1: Convert mixed numbers into improper fractions:
\[
4\frac{5}{12} = \frac{53}{12} \\
3\frac{11}{18} = \frac{65}{18} \\
2\frac{7}{24} = \frac{55}{24}
\]Step 2: Find LCM of 12, 18, and 24.
LCM (12, 18, 24) = 72
Convert each fraction to have denominator 72:
\[
\frac{53}{12} = \frac{318}{72} \\
\frac{65}{18} = \frac{260}{72} \\
\frac{55}{24} = \frac{165}{72}
\]Step 3: Add and subtract the fractions:\[
\frac{318}{72} + \frac{260}{72} – \frac{165}{72} = \frac{(318 + 260 – 165)}{72} = \frac{413}{72}
\]Step 4: Convert to mixed fraction:\[
\frac{413}{72} = 5\frac{53}{72}
\]Answer: \(5\frac{53}{72}\)
Q15: Subtract the sum of \(9\frac{3}{4}\) and \(3\frac{5}{6}\) from \(15\frac{7}{12}\).
Step 1: Convert all mixed numbers into improper fractions:
\[
9\frac{3}{4} = \frac{39}{4} \\
3\frac{5}{6} = \frac{23}{6} \\
15\frac{7}{12} = \frac{187}{12}
\]Step 2: Find the sum of the first two fractions:
We find LCM of 4 and 6:
LCM (4, 6) = 12
Convert both fractions to have denominator 12:
\[
\frac{39}{4} = \frac{117}{12} \\
\frac{23}{6} = \frac{46}{12} \\
\frac{117}{12} + \frac{46}{12} = \frac{163}{12}
\]Step 3: Subtract this sum from \(\frac{187}{12}\):\[
\frac{187}{12} – \frac{163}{12} = \frac{24}{12} = 2
\]Answer: 2
Q16: Subtract the sum of \(2\frac{5}{12}\) and \(3\frac{3}{4}\) from the sum of \(7\frac{1}{3}\) and \(5\frac{1}{6}\).
Step 1: Convert all mixed fractions to improper fractions.
\[
2\frac{5}{12} = \frac{29}{12} \\
3\frac{3}{4} = \frac{15}{4} \\
7\frac{1}{3} = \frac{22}{3} \\
5\frac{1}{6} = \frac{31}{6}
\]
Step 2: Find the sum of \(2\frac{5}{12}\) and \(3\frac{3}{4}\)
We need LCM of 12 and 4 = 12
\[
\frac{15}{4} = \frac{45}{12} \\
\frac{29}{12} + \frac{45}{12} = \frac{74}{12}
\]Step 3: Find the sum of \(7\frac{1}{3}\) and \(5\frac{1}{6}\)
LCM of 3 and 6 = 6
\[
\frac{22}{3} = \frac{44}{6} \\
\frac{44}{6} + \frac{31}{6} = \frac{75}{6}
\]Step 4: Subtract the two results:
First, convert both to a common denominator. LCM of 6 and 12 is 12.\[
\frac{75}{6} = \frac{150}{12} \\
\frac{74}{12} \text{ remains the same} \\
\frac{150}{12} – \frac{74}{12} = \frac{76}{12}
\]Reduce the fraction:\[
\frac{76}{12} = \frac{19}{3} = 6\frac{1}{3}
\]Answer: \(6\frac{1}{3}\)
Q17: What should be added to \(9\frac{4}{7}\) to get 16?
Step 1: Convert the mixed fraction \(9\frac{4}{7}\) to an improper fraction:\[
9\frac{4}{7} = \frac{(9 \times 7) + 4}{7} = \frac{63 + 4}{7} = \frac{67}{7}
\]Step 2: Let the number to be added be \(x\). According to the problem:\[
9\frac{4}{7} + x = 16
\]Convert 16 to a fraction with denominator 7 for easier calculation:\[
16 = \frac{16 \times 7}{7} = \frac{112}{7}
\]Step 3: Substitute values:\[
\frac{67}{7} + x = \frac{112}{7}
\]Step 4: Solve for \(x\):\[
x = \frac{112}{7} – \frac{67}{7} = \frac{112 – 67}{7} = \frac{45}{7}
\]Convert \(\frac{45}{7}\) back to mixed fraction:\[
\frac{45}{7} = 6\frac{3}{7}
\]Answer: \(6\frac{3}{7}\)
Q18: What must be subtracted from \(9\frac{1}{6}\) to get \(6\frac{1}{9}\)?
Step 1: Convert the mixed fractions into improper fractions:\[
9\frac{1}{6} = \frac{(9 \times 6) + 1}{6} = \frac{54 + 1}{6} = \frac{55}{6} \\
6\frac{1}{9} = \frac{(6 \times 9) + 1}{9} = \frac{54 + 1}{9} = \frac{55}{9}
\]Step 2: Let the number to be subtracted be \(x\). According to the problem:\[
9\frac{1}{6} – x = 6\frac{1}{9}
\]Substitute the improper fractions:\[
\frac{55}{6} – x = \frac{55}{9}
\]Step 3: Solve for \(x\):\[
x = \frac{55}{6} – \frac{55}{9}
\]To subtract, find the common denominator \(= 18\):\[
\frac{55}{6} = \frac{55 \times 3}{18} = \frac{165}{18} \\
\frac{55}{9} = \frac{55 \times 2}{18} = \frac{110}{18} \\
x = \frac{165}{18} – \frac{110}{18} = \frac{55}{18}
\]Step 4: Convert \(\frac{55}{18}\) to a mixed fraction:\[
\frac{55}{18} = 3\frac{1}{18}
\]Answer: \(3\frac{1}{18}\)
Q19: Of \(\frac{17}{20}\) and \(\frac{21}{25}\), which is greater and by how much?
Step 1: Find a common denominator to compare the two fractions.The denominators are 20 and 25. The Least Common Denominator (LCD) is:
LCD = LCM (20, 25) = 100
Step 2: Convert both fractions to equivalent fractions with denominator 100:\[
\frac{17}{20} = \frac{17 \times 5}{20 \times 5} = \frac{85}{100} \\
\frac{21}{25} = \frac{21 \times 4}{25 \times 4} = \frac{84}{100}
\]Step 3: Compare the numerators:\[
85 > 84
\]So, \(\frac{17}{20}\) is greater.
Step 4: Find how much greater:\[
\frac{17}{20} – \frac{21}{25} = \frac{85}{100} – \frac{84}{100} = \frac{1}{100}
\]Answer: \(\frac{17}{20}\) is greater than \(\frac{21}{25}\) by \(\frac{1}{100}\).
Q20: The sum of two fractions is \(14\frac{5}{12}\). If one of them is \(7\frac{2}{3}\), find the other.
Step 1: Convert the mixed fractions to improper fractions.\[
14\frac{5}{12} = \frac{14 \times 12 + 5}{12} = \frac{168 + 5}{12} = \frac{173}{12} \\
7\frac{2}{3} = \frac{7 \times 3 + 2}{3} = \frac{21 + 2}{3} = \frac{23}{3}
\]Step 2: Let the other fraction be \(x\). According to the problem:\[
x + \frac{23}{3} = \frac{173}{12}
\]Step 3: Subtract \(\frac{23}{3}\) from both sides to find \(x\):\[
x = \frac{173}{12} – \frac{23}{3}
\]Step 4: Find a common denominator for subtraction:\[
\text{LCD of } 12 \text{ and } 3 = 12
\]Convert \(\frac{23}{3}\) to denominator 12:\[
\frac{23}{3} = \frac{23 \times 4}{3 \times 4} = \frac{92}{12}
\]Step 5: Subtract the fractions:\[
x = \frac{173}{12} – \frac{92}{12} = \frac{173 – 92}{12} = \frac{81}{12}
\]Step 6: Simplify the fraction \(\frac{81}{12}\):
Divide numerator and denominator by 3:\[
\frac{81}{12} = \frac{27}{4}
\]Convert improper fraction to mixed fraction:\[
\frac{27}{4} = 6\frac{3}{4}
\]Answer: The other fraction is \(6\frac{3}{4}\).
Q21: From a piece of wire \(12\frac{3}{4}\) m long, a small piece of length \(3\frac{5}{6}\) has been cut off. What is the length of the remaining piece?
Step 1: Convert the mixed fractions to improper fractions.\[
12\frac{3}{4} = \frac{12 \times 4 + 3}{4} = \frac{48 + 3}{4} = \frac{51}{4} \\
3\frac{5}{6} = \frac{3 \times 6 + 5}{6} = \frac{18 + 5}{6} = \frac{23}{6}
\]Step 2: Subtract the cut piece from the total length:\[
\text{Remaining length} = \frac{51}{4} – \frac{23}{6}
\]Step 3: Find the least common denominator (LCD) of 4 and 6, which is 12.
Convert the fractions:\[
\frac{51}{4} = \frac{51 \times 3}{4 \times 3} = \frac{153}{12} \\
\frac{23}{6} = \frac{23 \times 2}{6 \times 2} = \frac{46}{12}
\]Step 4: Subtract the fractions:\[
\frac{153}{12} – \frac{46}{12} = \frac{153 – 46}{12} = \frac{107}{12}
\]Step 5: Convert \(\frac{107}{12}\) to a mixed fraction:\[
\frac{107}{12} = 8 \frac{11}{12}
\]Answer: The length of the remaining piece of wire is \(8\frac{11}{12}\) meters.
Q22: Three boxes weigh \(9\frac{1}{2}\) kg, \(14\frac{1}{5}\) kg and \(18\frac{3}{4}\) kg respectively. A porter carriers all the three boxes. What is the total weight carried by the porter?
Step 1: Convert the mixed fractions to improper fractions.\[
9\frac{1}{2} = \frac{9 \times 2 + 1}{2} = \frac{18 + 1}{2} = \frac{19}{2} \\
14\frac{1}{5} = \frac{14 \times 5 + 1}{5} = \frac{70 + 1}{5} = \frac{71}{5} \\
18\frac{3}{4} = \frac{18 \times 4 + 3}{4} = \frac{72 + 3}{4} = \frac{75}{4}
\]Step 2: Find the least common denominator (LCD) of 2, 5, and 4.
– Prime factors:
– 2 = 2
– 5 = 5
– 4 = \(2^2\)
LCD = \(2^2 \times 5 = 4 \times 5 = 20\)
Step 3: Convert all fractions to denominator 20.\[
\frac{19}{2} = \frac{19 \times 10}{2 \times 10} = \frac{190}{20} \\
\frac{71}{5} = \frac{71 \times 4}{5 \times 4} = \frac{284}{20} \\
\frac{75}{4} = \frac{75 \times 5}{4 \times 5} = \frac{375}{20} \\
\]Step 4: Add the fractions.\[
\frac{190}{20} + \frac{284}{20} + \frac{375}{20} = \frac{190 + 284 + 375}{20} = \frac{849}{20}
\]Step 5: Convert \(\frac{849}{20}\) to a mixed fraction.\[
\frac{849}{20} = 42 \frac{9}{20}
\]Answer: The total weight carried by the porter is \(42\frac{9}{20}\) kilograms.
Q23: On one day, a labourer earned ₹125. Out of this money, he spent ₹\(68\frac{1}{2}\) on food, ₹\(20\frac{3}{4}\) on tea and ₹\(16\frac{2}{5}\) on other eatables. How much does he save on that day?
Step 1: Convert the mixed fractions to improper fractions.\[
68\frac{1}{2} = \frac{68 \times 2 + 1}{2} = \frac{136 + 1}{2} = \frac{137}{2} \\
20\frac{3}{4} = \frac{20 \times 4 + 3}{4} = \frac{80 + 3}{4} = \frac{83}{4} \\
16\frac{2}{5} = \frac{16 \times 5 + 2}{5} = \frac{80 + 2}{5} = \frac{82}{5}
\]Step 2: Find the least common denominator (LCD) of 2, 4, and 5.
– Prime factors:
– 2 = 2
– 4 = \(2^2\)
– 5 = 5
LCD = \(2^2 \times 5 = 4 \times 5 = 20\)
Step 3: Convert all fractions to denominator 20.\[
\frac{137}{2} = \frac{137 \times 10}{2 \times 10} = \frac{1370}{20} \\
\frac{83}{4} = \frac{83 \times 5}{4 \times 5} = \frac{415}{20} \\
\frac{82}{5} = \frac{82 \times 4}{5 \times 4} = \frac{328}{20}
\]Step 4: Add the expenditures.\[
\frac{1370}{20} + \frac{415}{20} + \frac{328}{20} = \frac{1370 + 415 + 328}{20} = \frac{2113}{20}
\]Step 5: Convert ₹125 into fraction with denominator 20.\[
125 = \frac{125 \times 20}{20} = \frac{2500}{20}
\]Step 6: Calculate savings.\[
\text{Savings} = \frac{2500}{20} – \frac{2113}{20} = \frac{2500 – 2113}{20} = \frac{387}{20}
\]Step 7: Convert \(\frac{387}{20}\) into mixed fraction.\[
\frac{387}{20} = 19 \frac{7}{20}
\]Answer: The labourer saves ₹\(19\frac{7}{20}\) on that day.