
Basic Calculator
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FAQs
- How do I use this online calculator?
- Click the keys or type on your keyboard — digits, + − × ÷, Enter for equals, Escape to clear, Backspace to delete. The result appears on the display and in the history below.
- Does the calculator follow order of operations?
- Yes. Multiplication and division are evaluated before addition and subtraction, and you can use parentheses to group parts of a calculation, e.g. (2 + 3) × 4 = 20.
- What do the MC, MR, M+ and M− keys do?
- They control the memory register: M+ adds the current value to memory, M− subtracts it, MR types the stored value into your calculation, and MC clears the memory. An M indicator shows when memory holds a value.
- How does the percent key work?
- The % key divides the preceding number by 100, so 50% is 0.5 and 200 × 10% is 20. To add 10% to 200, calculate 200 + 200 × 10%.
- Can I reuse an earlier calculation?
- Yes — every completed calculation is kept in the history tape below the keypad. Click any entry to load its expression back into the display.
- Why does it say “Division by zero”?
- Dividing any number by zero has no defined value in arithmetic, so the calculator shows an error instead of a misleading result. Correct the divisor and press = again.
What is this online calculator?
A free on-screen calculator for everyday arithmetic: addition, subtraction, multiplication, division, percentages and square roots. It follows the standard order of operations, supports parentheses, and keeps a history tape of your recent calculations so you can reuse them with one click.
How to use this calculator
- Click the keys — or just type: digits, + − × ÷, Enter for equals, Escape to clear, Backspace to delete.
- Use parentheses to group operations: (2 + 3) × 4 = 20.
- Press % to divide the previous number by 100 — 200 × 10% = 20.
- Press = to calculate. The result stays on screen and is saved to the history below.
Memory keys
The memory register works like a pocket calculator's: M+ adds the current value to memory, M− subtracts it, MR recalls the stored value into your calculation, and MC clears it. An M appears on the display while memory holds a value.
Limitations
- Results are computed in double-precision floating point — exact to about 15 significant digits.
- Division by zero and other undefined operations show an error instead of a wrong answer.
- For trigonometry, logarithms and powers, use the scientific calculator.
