One pair of brackets is to be placed in the equation below to make it correct.
3 × 7 + 5 – 6 × 2 = 24
Which of the following is the correct placement?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 3 × (7 + 5) – 6 × 2 = 24
By BODMAS, the part inside the brackets is worked out first, then × and ÷, then + and –. Work out the left side of each placement.
Option (1): \(7+5=12\), then \(3\times12=36\) and \(6\times2=12\)
\(36-12=24\), which equals the right side
Why the other options are incorrect
Option (2) (3 × 7 + 5 – 6) × 2 — Incorrect. \((21+5-6)\times2=20\times2=\) 40, not 24.
Option (3) 3 × 7 + (5 – 6) × 2 — Incorrect. \(21+(-1)\times2=21-2=\) 19, not 24.
Option (4) 3 × (7 + 5 – 6) × 2 — Incorrect. \(3\times6\times2=\) 36, not 24.