JavaScript
Operators & expressions
A practical reference with examples you can run.
Introduction
An expression produces a value. Arithmetic operators combine numbers, and comparison operators answer questions. Parentheses make the intended order explicit and help the reader follow a calculation.
Syntax & example
const total = (12 + 8) * 2; console.log(total);
Expected output
40
Common mistakes
- Using a variable before assigning a value to it.
- Mixing text and numbers without converting deliberately.
- Skipping an empty input or a boundary value when testing.
Practice
Calculate the total cost of three items priced at 12 each.
main.jsYour ideas, in code.
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