Transparent calculators with visible methods, assumptions, and limits.
Google-style four-function calculator
This page replicates the core behavior of the Google calculator: enter two numbers and pick an operation to see the result instantly, with a small chart that visualizes the last operation. All arithmetic uses full internal precision; only the displayed values are rounded.
Calculator
Result: 15
Operation: 10 + 5
How the arithmetic is done
The single calculation function window.wpcCalculate({a, b, op}) returns an object with value, formula, and error. It validates that inputs are finite and that division by zero is impossible. The same function populates the live result, the quick answer, the chart, and every worked example below.
Worked examples
Adding 12 and 4
Inputs: A = 12, B = 4, Operation = +
Calculation: result pending
Subtracting 15 from 100
Inputs: A = 100, B = 15, Operation = −
Calculation: result pending
Multiplying 7 by 8
Inputs: A = 7, B = 8, Operation = ×
Calculation: result pending
Common pitfalls
Floating-point rounding in division. 1 ÷ 3 cannot be represented exactly in binary floating point, so the displayed value is an estimate. For exact fractions, use a symbolic calculator.
Very large or very small numbers lose precision. JavaScript uses 64-bit floats; integers above 253 or below −253 may not be represented exactly.
Division by zero is blocked. The calculator rejects B = 0 when op = ÷ and shows an error instead of Infinity or NaN.
Negative zero edge case. Multiplying 0 by -1 yields -0, which behaves like 0 in most contexts but can appear in string representations.
Boundary scenarios
Maximum safe integer. Try A = 9007199254740991 (Number.MAX_SAFE_INTEGER) and B = 1 with addition. The exact integer result 9007199254740992 is representable; the next integer 9007199254740993 is not.
Underflow to zero. Multiplying two very small numbers (e.g., 1e-200 × 1e-200) yields 0 due to underflow, even though the mathematical product is non-zero.
Comparison: when to use a different tool
| Need | This calculator | Better tool |
|---|---|---|
| Basic + − × ÷ | Yes | — |
| Exponents, roots, trig | No | Scientific calculator |
| Exact fractions | No | Symbolic math app |
| High-precision decimals | No | Arbitrary-precision library |
Frequently asked questions
Why does 0.1 + 0.2 not equal 0.3?
Because 0.1 and 0.2 cannot be represented exactly in binary floating point. The actual stored values are slightly different, so their sum is 0.30000000000000004. This is a property of IEEE 754 arithmetic, not a bug in the calculator.
Can I chain operations like 2 + 3 × 4?
No. This calculator performs one operation at a time on two operands. To compute 2 + 3 × 4, first multiply 3 × 4 = 12, then add 2 + 12 = 14, using the result of the first step as A in the second.
How do I enter very large numbers?
Type or paste them directly into the input fields. The calculator accepts numbers up to roughly ±1e15, but precision degrades beyond ±253 for integers.
Is the result exact?
Addition, subtraction, and multiplication are exact for integers within the safe range. Division and non-integer results are floating-point estimates with up to 15–17 significant digits.
Sources
The calculator logic and numeric behavior are grounded in the ECMAScript and IEEE 754 standards. The links below explain the numeric representation and limits used by the implementation.
- ECMAScript Number values (ECMA-262) — defines JavaScript numeric representation, safe integer range, and arithmetic behavior.
- IEEE 754 floating-point standard — explains binary floating-point representation, rounding, and edge cases such as 0.1 + 0.2 ≠ 0.3.