Basic calculator
For everyday sums: four operations and percent. Works with buttons and keyboard.
0
How to use it
- Type digits with the buttons or the keyboard; use the point or comma key for decimals.
- Operations: + − × ÷ (keyboard + - * /). Press “=” or Enter for the result.
- Operations run one after another, left to right: 2 + 3 × 4 = 20 (no operator precedence, like a plain pocket calculator).
- C clears everything, CE clears only the current number, ⌫ or Backspace deletes the last digit, ± changes the sign.
- Percent (%): 200 + 10 % = 220 (10 % means 10 percent of 200, i.e. 20); 200 × 10 % = 20; on its own 50 % = 0.5.
- Division by zero is not possible: the calculator tells you so.
Examples
Examples compiled by the author:
| Input | Result |
|---|---|
| 0.1 + 0.2 = | 0.3 |
| 1 ÷ 3 × 3 = | 1 |
| 1,200,000 × 12 % = | 144,000 |
| 500,000 + 12 % = | 560,000 |
| 250,000 − 20 % = | 200,000 |
Accuracy and limits
- Computers store fractions in binary, so 0.1 + 0.2 normally gives 0.30000000000000004; this calculator rounds the result to 15 significant digits and hides that error.
- The screen shows up to 12 significant digits; an entered number has at most 15 digits.
- This is a general-purpose calculator: use the dedicated calculators for VAT and depreciation.
Related
Sources
- Calculation method: ordinary arithmetic, written and tested by the author.