What will come in place of the question mark (?) in the following equation, if ‘+’ and ‘–’ are interchanged and ‘×’ and ‘÷’ are interchanged? 229 ÷ 41 + 502 × 2 – 44 = ?

Correct — B. Swap the symbols first, then evaluate the new expression by BODMAS.

Rule: + becomes −, − becomes +, × becomes ÷, ÷ becomes ×.

So 229 ÷ 41 + 502 × 2 − 44 is read as 229 × 41 − 502 ÷ 2 + 44.

229 × 41 = 9389
502 ÷ 2 = 251
9389 − 251 = 9138
9138 + 44 = 9182 → option (b)

Why the others are wrong

• (a)
  9218 — 9218 ends in 8. The last step adds 44 to 9138, so the answer must end in 2 — this fails on the units digit alone.
• (c)
  9812 — 9812 cannot be right because 229 × 41 = 9389 and subtracting 251 already puts you at 9138. The answer has to begin 91, not 98.
• (d)
  9281 — 9281 ends in 1, and 9138 + 44 ends in 2. It uses the same four digits as the correct value, which is exactly why it is offered.

In a sign-substitution item the printed expression is a disguise. Rewrite it with the swapped symbols before any arithmetic, then apply BODMAS to the rewritten line: division and multiplication first, then addition and subtraction, left to right.

The wrong options here are all rearrangements of the digits 9, 1, 8 and 2, so the working has to be carried through to the exact value.

Two cheap checks catch most slips — the leading digits, fixed once 229 × 41 is done, and the units digit, fixed by the final addition.

Key facts

• Rewrite the expression with the swapped symbols before you calculate anything.
• BODMAS still governs the rewritten line — the swap changes the symbols, not the order of operations.
• 229 × 41 = 9389 and 502 ÷ 2 = 251.

Common traps

• Swapping one pair of symbols and leaving the other pair as printed.
• Working the swapped line strictly left to right instead of by BODMAS.

No directly related past PYQ was found.