If * means -, + means /, - means * and / means +, then 16 - 2 / 600 + 90 * 100…

Concept: In symbol-substitution arithmetic questions, first replace every occurrence of a symbol with the operation it actually represents throughout the expression, then evaluate the resulting expression using the standard order of operations (multiplication and division before addition and subtraction, working left to right).

Application: Substitute each symbol with its true operation, then apply order of operations:

1. The symbol − actually represents multiplication (×), so 16 − 2 becomes 16 × 2.

2. The symbol / actually represents addition (+), so the next operator becomes +.

3. The symbol + actually represents division (÷), so the next operator becomes ÷.

4. The symbol * actually represents subtraction (−), so the last operator becomes −.

5. Substituting all four gives the expression: 16 × 2 + 600 ÷ 90 − 100.

6. Apply order of operations: compute the multiplication and division first — 16 × 2 = 32 and 600 ÷ 90 ≈ 6.67.

7. Combine the addition and subtraction terms left to right: 32 + 6.67 − 100 = −61.33.

Cross-check: Re-checking the substitution independently: swapping (−, ×) and (/, +) is a symmetric pair-swap, so re-applying it to the transformed expression restores the original layout, confirming no operator was mis-mapped. The final value, −61.33, matches the correct option to two decimal places.