Standard Calculator – Basic Math Operations
Perform addition, subtraction, multiplication, division and more with this standard calculator.
About This Calculator
Perform addition, subtraction, multiplication, division and more with this standard calculator. Use the calculator above for instant results.
Understanding the Six Basic Operations
A two-number calculator applies one selected operation to an ordered pair of inputs. Addition and multiplication combine quantities; subtraction and division compare them in an order-sensitive way; exponentiation uses the second input as a power; modulo reports a division remainder. Because this page performs one operation at a time, a long expression such as 2+3×4 is not evaluated as a complete PEMDAS expression here.
The order of the inputs matters for subtraction, division, powers, and modulo. For example, 12÷3=4 while 3÷12=0.25. Division and modulo also require a nonzero second input. Exponents introduce additional mathematical cases: a negative exponent represents a reciprocal, while a fractional exponent can represent a root when the real-number domain permits it.
Inverse operations provide a useful mental check. Addition can be checked with subtraction, multiplication with division, and a power can sometimes be checked with an appropriate root. For instance, if 37+18=55, then 55-18 should return 37. These relationships help detect data-entry mistakes without repeating the identical calculation.
Signs also deserve attention. Multiplying or dividing numbers with the same sign gives a positive result, while different signs give a negative result. Subtracting a negative number is equivalent to adding its opposite. Writing the operation explicitly before pressing Calculate makes sign errors easier to catch.
| Operation | Rule | Key restriction or meaning |
|---|---|---|
| Addition | a+b | Commutative: a+b=b+a |
| Subtraction | a-b | Order matters |
| Multiplication | a×b | Commutative |
| Division | a/b | b must not be zero |
| Power | ab | b controls repeated powers or roots |
| Modulo | a % b | Remainder convention can vary for negatives |
For decimal results, remember that a calculator displays a finite representation. Some fractions terminate in decimal form, such as 1/8=0.125, while others repeat, such as 1/3. A displayed decimal may therefore be rounded even when the underlying mathematical value is exact.
Worked Examples
- 25 + 4 = 29
Answer: 29
- 100 ÷ 8 = 12.5
Answer: 12.5
- 2^10 = 1,024
Answer: 1,024
- 17 = 5×3 + 2
Answer: 2
- 2-3 = 1 / 23 = 1/8
Answer: 0.125
Who Uses This Calculator?
Quick arithmetic for homework.
Fast calculations on the go.
Verify basic math quickly.
Demo arithmetic operations.
Common Mistakes to Avoid
❌ Order of operations
PEMDAS/BODMAS: Parentheses, Exponents, Multiply/Divide, Add/Subtract. This calculator handles one operation at a time.
❌ Floating point precision
Computers store decimals in binary. 0.1 + 0.2 may show 0.30000000000000004. This is normal — round to desired precision.
❌ Dividing or taking modulo by zero
Division by zero is undefined, and a remainder modulo zero is not defined. Check the second input before using either operation.
❌ Treating modulo as percentage
The % operation on this page means remainder after division. For example, 17 % 5 = 2; it does not mean 17 percent of 5.
Frequently Asked Questions
What is PEMDAS?
Order of operations: Parentheses, Exponents, Multiplication, Division, Addition, Subtraction. Determines which operations to perform first.
What is modulo?
The remainder after division. 17 mod 5 = 2 because 17 = 5×3 + 2. Used in programming and number theory.
What is a power?
A number multiplied by itself n times. 2^10 = 2×2×2×2×2×2×2×2×2×2 = 1,024.
Does this calculator evaluate a full expression?
No. It takes two numbers and applies one selected operation. For a multi-operation expression, evaluate the required steps in the correct order or use a scientific expression calculator.
What does a negative exponent mean?
For a nonzero base, a negative integer exponent means take the reciprocal: a-n=1/an. For example, 2-3=1/8=0.125.
Why is division not commutative?
Changing the order changes which number is divided by which. In general a/b is not equal to b/a; for example, 12/3=4 while 3/12=0.25.
Can modulo results differ between systems for negative numbers?
Yes. Programming languages and mathematics texts can use different sign conventions for remainders. For negative inputs, check the convention used by the implementation before comparing results.
Formula Explorer connections
Interpretation: This relationship converts, summarizes or checks numerical quantities using standard arithmetic and measurement rules. Assumption: Use consistent units, preserve enough significant digits, and round only the final result unless the method states otherwise.