Step 1: Perform the operation inside the parentheses first.
2+5=7
Step 2: Multiply the result by 3.
3×7=21
Answer: 3 × (2 + 5) = 21. Without parentheses, 3 × 2 + 5 would equal 11, because multiplication is performed before addition by default.
Why It Matters
Parentheses control the order of operations in every branch of mathematics. In the standard order of operations (PEMDAS/BODMAS), expressions inside parentheses are always evaluated first. Misplacing or omitting parentheses changes the meaning of an expression entirely, which is why they are essential in algebra, calculus, and programming.
Common Mistakes
Mistake: Ignoring parentheses and applying the default order of operations instead.
Correction:Always evaluate the expression inside parentheses before performing any operations outside them. For example, in 2×(3+4), compute 3+4 first, not 2×3.
Reference LibraryMathwords