Question

Which two operation signs need to be interchanged to make the following equation correct? \[ 73 - 13 \times 42 \div 14 + 56 = 56 \]

• A. $+$ and $\times$
• B. $\times$ and $\div$
• C. $-$ and $+$
• D. $-$ and $\times$

Hint:

For operator interchange: - Try options one by one - Use BODMAS carefully - Stop when equation satisfies

Answer 1

The Correct Option is A

Concept: We test by interchanging given operators and check which makes LHS = RHS.

Step 1: Interchange $+$ and $\times$.
\[ 73 - 13 + 42 \div 14 \times 56 \]

Step 2: Solve using BODMAS.
\[ 42 \div 14 = 3 \] \[ 3 \times 56 = 168 \] \[ 73 - 13 + 168 \] \[ = 60 + 168 = 228 \quad (\text{not correct}) \]

Step 3: Check $\times$ and $\div$.
\[ 73 - 13 \div 42 \times 14 + 56 \] \[ 13 \div 42 \times 14 = \frac{13}{3} \] Not equal → reject.

Step 4: Check $-$ and $+$.
\[ 73 + 13 \times 42 \div 14 - 56 \] \[ 13 \times 42 = 546,\quad 546 \div 14 = 39 \] \[ 73 + 39 - 56 = 56 \]

Step 5: Final conclusion.
Thus, correct interchange is: \[ $-$ and $+$ \]