Compute 21 - 6(4 - 1).

• A. 3
• B. 9
• C. 7
• D. 1

Answer: (A)

The key idea is to follow the order of operations: handle parentheses first, then multiply, then subtract. Inside the parentheses, 4 minus 1 equals 3. Then multiply: 6 times 3 is 18. Finally, subtract that from 21: 21 minus 18 equals 3. So the value is 3. This outcome comes from applying the operations in the correct order; doing any step out of order would lead to a different result, which is why the other possible numbers don’t fit.