Select the correct combination of mathematical signs that can sequentially replace the * signs and make the equation correct.
512 * 32 * 9 * 100 * 6 * 25 * 2
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → ÷, ×, –, +, =, ×
Put the signs of an option in place of the * signs in order, and work out each side of ‘=’ by BODMAS. The option is right only when the two sides are equal.
With ÷, ×, –, +, =, × the equation reads 512 ÷ 32 × 9 – 100 + 6 = 25 × 2
\(512\div32=16\) and \(16\times9=144\)
Left side \(=144-100+6=50\)
Right side \(=25\times2=50\), so the two sides are equal
Why the other options are incorrect
Option (1) ÷, ×, +, =, –, × — Incorrect. 512 ÷ 32 × 9 + 100 = 6 – 25 × 2 gives 244 on the left and –44 on the right.
Option (2) ÷, ×, +, –, =, × — Incorrect. 512 ÷ 32 × 9 + 100 – 6 = 25 × 2 gives 238 on the left and 50 on the right.
Option (4) +, ×, ÷, =, –, × — Incorrect. 512 + 32 × 9 ÷ 100 = 6 – 25 × 2 gives 514.88 on the left and –44 on the right.