Exercise: 1-C
Q1: 18 – (20 – 15 ÷ 3)
Step 1: First, divide 15 by 3 → 15 ÷ 3 = 5
Step 2: Then subtract the result from 20 → 20 – 5 = 15
Step 3: Finally, subtract this from 18 → 18 – 15 = 3
Q2: -15 + 24 ÷ (15 – 13)
Step 1: Solve inside the bracket first → 15 – 13 = 2
Step 2: Now divide → 24 ÷ 2 = 12
Step 3: Add the result to -15 → -15 + 12 = -3
Q3: \(35-\left\{15+14-\left(13+\overline{2-1+3}\right)\right\}\)
Step 1: Solve underlined: 2 – 1 + 3 = 4
Step 2: Now inside the brackets → 13 + 4 = 17
Step 3: Add 15 + 14 = 29
Step 4: Subtract → 29 – 17 = 12
Step 5: Final answer → 35 – 12 = 23
Q4: \(27-\left\{13+4-\left(8+4-\overline{1+3}\right)\right\}\)
Step 1: Underlined part → 1 + 3 = 4
Step 2: Inner bracket → 8 + 4 = 12, then 12 – 4 = 8
Step 3: Now 13 + 4 = 17
Step 4: 17 – 8 = 9
Step 5: 27 – 9 = 18
Q5: \(32-\left[43-\left\{51-\left(20-\overline{18-7}\right)\right\}\right] \)
Step 1: 18 – 7 = 11
Step 2: 20 – 11 = 9
Step 3: 51 – 9 = 42
Step 4: 43 – 42 = 1
Step 5: 32 – 1 = 31
Q6: \(46-\left[26-\left\{14-\left(15-4\div2\times2\right)\right\}\right] \)
Step 1: Start with division → 4 ÷ 2 = 2
Step 2: Multiply result → 2 × 2 = 4
Step 3: 15 – 4 = 11
Step 4: 14 – 11 = 3
Step 5: 26 – 3 = 23
Step 6: 46 – 23 = 23
Q7: \(45-\left[38-\left\{60\div3-\left(6-9\div3\right)\div3\right\}\right] \)
Step 1: Divide → 9 ÷ 3 = 3
Step 2: 6 – 3 = 3 → 3 ÷ 3 = 1
Step 3: 60 ÷ 3 = 20
Step 4: 20 – 1 = 19
Step 5: 38 – 19 = 19
Step 6: 45 – 19 = 26
Q8: \(17-\left[17-\left\{17-\left(17-\overline{17-17}\right)\right\}\right] \)
Step 1: 17 – 17 = 0
Step 2: 17 – 0 = 17
Step 3: 17 – 17 = 0
Step 4: 17 – 0 = 17
Step 5: 17 – 17 = 0
Q9: \(2550-\left[510-\left\{270-\left(90-\overline{80+7}\right)\right\}\right] \)
Step 1: 80 + 7 = 87
Step 2: 90 – 87 = 3
Step 3: 270 – 3 = 267
Step 4: 510 – 267 = 243
Step 5: 2550 – 243 = 2307
Q10: \(30+\left[\left\{-2\times25-\overline{13-3}\right\}\right] \)
Step 1: 13 – 3 = 10
Step 2: 25 – 10 = 15
Step 3: -2 × 15 = -30
Step 4: 30 + (-30) = 0
Q11: \(88-\left\{5-\left(-48\right)\div\left(-16\right)\right\}\)
Step 1: -48 ÷ -16 = 3
Step 2: 5 – 3 = 2
Step 3: 88 – 2 = 86
Q12: \(9\times(8-\overline{3+2})-2(2+\overline{13-3})\ \)
Step 1: 3 + 2 = 5 → 8 – 5 = 3
Step 2: 9 × 3 = 27
Step 3: 3 + 3 = 6 → 2 + 6 = 8
Step 4: 2 × 8 = 16
Step 5: 27 – 16 = 11
Q13: \(2-\left[3-\left\{6-\left(5-\overline{4-3}\right)\right\}\right] \)
Step 1: 4 – 3 = 1
Step 2: 5 – 1 = 4
Step 3: 6 – 4 = 2
Step 4: 3 – 2 = 1
Step 5: 2 – 1 = 1
