What will replace ‘?’ in the following equation if ‘+’ and ‘÷’ are…

Concept

When mathematical operation symbols are interchanged, first replace every affected symbol with its paired symbol.

Then evaluate the transformed expression using the standard order of operations: multiplication and division before addition and subtraction, proceeding left to right within the same priority.

Application

Applying the stated interchanges changes the expression as follows:

1. Replace × with −, − with ×, ÷ with +, and + with ÷: 16 − 4 × 3 + 21 ÷ 3.

2. Evaluate multiplication and division: 4 × 3 = 12 and 21 ÷ 3 = 7.

3. Substitute these values: 16 − 12 + 7.

4. Evaluate from left to right: 16 − 12 = 4, and 4 + 7 = 11.

Cross-check

Directly evaluating the transformed expression gives 16 − 12 + 7 = 11, confirming the same result.

Therefore, the value that replaces ‘?’ is 11.