A basic calculator adds, subtracts, multiplies, divides or raises one number to the power of another and shows the result instantly. Formula: Result = A ⊕ B for ⊕ in {add, sub, mul, div, pow}, with divide-by-zero rejected. With 12 and 3 you get 15, 9, 36, 4 or 1,728.
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How to use the basic calculator
- Enter the first number as A.
- Enter the second number as B.
- Choose add, subtract, multiply, divide or power.
- Read the result.
Basic calculator operations
- Add: A + B
- Subtract: A − B
- Multiply: A × B
- Divide: A ÷ B (B cannot be 0)
- Power: A raised to the power B, AB
The basic calculator works on two numbers at a time and shows the result to up to eight decimal places. Negative numbers and decimals are accepted.
Basic calculator worked example
| Calculation | Result |
|---|---|
| 12 + 3 | 15 |
| 12 − 3 | 9 |
| 12 × 3 | 36 |
| 12 ÷ 3 | 4 |
| 12 ^ 3 | 1,728 |
| 2 ^ 10 | 1,024 |
| 7 ÷ 2 | 3.5 |
| 2 ^ 0.5 | 1.41421356 |
With the default values A = 12 and B = 3, adding gives 15, subtracting 9, multiplying 36 and dividing 4. The power option gives 12 × 12 × 12 = 1,728. A power of 0.5 is a square root, so 2 ^ 0.5 is about 1.41421356.
Longer calculations and order of operations
Because the basic calculator handles one operation at a time, work through longer expressions in steps using the standard order of operations: brackets first, then powers, then multiplication and division from left to right, then addition and subtraction from left to right. For 2 + 3 × 4, multiply first, 3 × 4 = 12, then add 2 to get 14, not 20. For (2 + 3) × 4, the brackets come first, so the answer is 20. Write down each intermediate result, or carry it into A for the next step.
Division, negatives and powers
- Dividing by zero has no answer, so the calculator shows a message instead of a number.
- A negative number raised to a fractional power, such as (−8) ^ 0.5, is not a real number and is rejected.
- Any non-zero number to the power 0 is 1, and a negative power is a reciprocal: 2 ^ −3 = 1 ÷ 8 = 0.125.
- Results too large to represent, such as 10 ^ 400, are also rejected.
Why some decimals look odd
Computers store most decimal fractions in binary, which cannot represent numbers such as 0.1 exactly. In raw form, 0.1 + 0.2 comes out as 0.30000000000000004. The basic calculator rounds its display to eight decimal places, which hides this tiny error for everyday use, so 0.1 + 0.2 shows as 0.3. For money, round the final answer to cents. For exact work with very large whole numbers, use a big number calculator instead.
Quick percentage tricks
You can use the multiply option for percentages: to find 15% of 80, multiply 80 by 0.15 to get 12. To add 8% tax to $45, multiply 45 by 1.08 for $48.60. To reverse a percentage increase, divide: $48.60 ÷ 1.08 = $45. For more complex percentage questions, a dedicated percentage calculator shows each step.
Everyday uses for a basic calculator
Most daily arithmetic needs only the four operations. Splitting a $96 restaurant bill between four people is 96 ÷ 4 = $24 each. Working out how many 12-packs make 150 cans is 150 ÷ 12 = 12.5, so you need 13 packs. Checking a pay stub is a chain of steps: hours × rate, then subtract each deduction in turn. Comparing unit prices is division too: a 750 g box at $4.50 costs 4.50 ÷ 750 = $0.006 per gram, while a 500 g box at $3.20 costs $0.0064 per gram, so the bigger box is cheaper.
The power option helps with growth questions. Something that doubles 10 times grows by 2 ^ 10 = 1,024 times, and $100 growing 5% a year for 10 years becomes 100 × 1.05 ^ 10, about $162.89. Do the power first with the basic calculator, then multiply the result by 100 in a second step. Keeping each step visible makes it easy to spot a typing mistake, which is the most common source of wrong answers.
Related converters and calculators
Related calculators:
- Scientific calculator: functions
- Percentage calculator: percentages
- Fraction calculator: fractions
- Big number calculator: large numbers
Sources
OpenStax Prealgebra 2e, 2.1: Use the language of algebra; OpenStax Prealgebra 2e, 1.5: Divide whole numbers.
Questions about this calculator
What is 12 to the power of 3?
1,728.
Can I divide by zero?
No. Division by zero has no answer.
Why does 0.1 + 0.2 look wrong in some calculators?
Binary storage cannot represent 0.1 exactly; rounding hides the error.
How do I do longer calculations?
Work in steps using the order of operations.
How do I find a percentage?
Multiply by the percentage as a decimal, e.g. 80 × 0.15 = 12.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
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