How This Calculation Works
Type or tap an expression using the number pad. The calculator supports the four basic operations (+, −, ×, ÷), parentheses for grouping, the modulo operator (%), and decimal numbers. Press = or Enter to evaluate. Every calculation is saved in a scrollable history you can clear at any time.
Internally the expression is parsed with a recursive-descent parser — no eval() — so only valid arithmetic is executed.
Common Mistakes to Avoid
- Forgetting operator precedence. Multiplication and division happen before addition and subtraction. Use parentheses to override:
2 + 3 × 4 = 14, but(2 + 3) × 4 = 20. - Division by zero. Dividing any number by zero returns an error. Check the denominator before dividing.
- Floating-point precision. Computers represent decimals in binary, so
0.1 + 0.2may show0.300000000004. The calculator rounds to 12 significant digits to minimize this.
Worked Example
Shopping split: Three friends buy items costing $12.50, $8.75, and $15.00. Total: 12.50 + 8.75 + 15 = $36.25. Per person: 36.25 ÷ 3 ≈ $12.08.
Nested parentheses: (10 + 5) × (20 − 8) ÷ 3 → 15 × 12 ÷ 3 = 60.