Mind the Mistake, Mend the Mistake (Page 87)

Transcript

Mind the Mistake, Mend the Mistake (Page 87)Some simplifications are shown below where the letter-numbers are replaced by numbers and the value of the expression is obtained. Observe each of them and identify if there is a mistake. If you think there is a mistake, try to explain what might have gone wrong. Then, correct it and give the value of the expression. Now, 10 – a = 6 Putting a = –4 10 – (–4) = 6 10 + 4 = 6 14 = 6 Which is incorrect Correct statement could be 10 – (-a) = 14 Now, 3d = 36 Putting d = 6 3 × 6 = 36 18 = 36 Which is incorrect Correct statement could be 3d = 18 Now, 3s – 2 = 15 Putting s = 7 3 × 7 – 2 = 15 21 – 2 = 15 19 = 16 Which is incorrect Correct statement could be 3s – 2 = 19 Now, 2r + 1 = 29 Putting r = 8 2 × 8 + 1 = 29 16 + 1 = 29 17 = 29 Which is incorrect Correct statement could be 2r + 1 = 17 Now, 2j = 10 Putting j = 5 2 × 5 = 10 10 = 10 Which is correct So, this statement is correct Now, 3 (m + 1) = 19 Putting m = –6 3 × (–6 + 1) = 19 –3 × (6 – 1) = 19 –3 × 5 = 19 –15 = 19 Which is incorrect Correct statement could be 3 (m + 1) = –15 Now, 2f – 2g = 2 Putting f = 3, g = 1 2 × 3 – 2 × 1 = 2 6 – 2 = 2 4 = 2 Which is incorrect Correct statement could be 2f – 2g = 4 Now, 2t + b = 24 Putting t = 4, b = 3 2 × 4 + 3 = 24 8 + 3 = 24 11 = 24 Which is incorrect Correct statement could be 2t + b = 11 Now, h – (3 – n) = 4 Putting h = 5, n = 6 5 – (3 – 6) = 4 5 – (–3) = 4 5 + 3 = 4 8 = 4 Which is incorrect Correct statement could be h – (3 – n) = 8