Basic Calculator
Add, subtract, multiply or divide two numbers.
Calculator display:
0
Keyboard: digits, + - * /, Enter forequals=, Esc to clear, Backspace to delete.
Worked example
12 + 8 = 20. Enter the first number, tap an operator, enter the second number, then tap =.
How it works
Each key press builds up one calculation: a number, an operator, and a second number. Tapping another operator before = carries the running total forward, the way an everyday pocket calculator does. This tool is deliberately simple, with no operator precedence or brackets. For expressions with precedence, powers, roots or trigonometry, see the Scientific Calculator.
What this result means
The display shows the running total of the calculation you have built up with the keypad.
Common mistakes
- Expecting brackets or operator precedence: this is a keypad calculator, not an expression parser. For precedence, powers, roots or trigonometry, use the Scientific Calculator instead.
Assumptions and limitations
- Two operands and one operator at a time, chained as you go — not a typed expression.