Subtraction Calculator

Subtraction takes one amount away from another, or finds the gap between two numbers. If you have 12 apples and eat 5, 12 − 5 = 7 are left. The answer is called the difference. This subtraction calculator subtracts whole numbers, decimals and negative numbers, and for ordinary cases it shows the column method, including every borrow, step by step.

• Minuend: the number you start with (the first number, 12 in 12 − 5).
• Subtrahend: the number you take away (5 in 12 − 5).
• Difference: the answer (7 in 12 − 5 = 7).

Write the bigger number on top, line up the units, tens and hundreds, and subtract one column at a time from the right. When the top digit is smaller than the digit below it, borrow 1 from the next column to the left. That 1 is worth 10 in the column you are working on. Here is 502 − 267.

1. Units: 2 is smaller than 7, so we need to borrow. The tens digit is 0, so we borrow from the hundreds: 5 becomes 4, the 0 becomes 9 (after lending), and the units become 12. Now 12 − 7 = 5.
2. Tens: the top digit is now 9, and 9 − 6 = 3.
3. Hundreds: the top digit is now 4, and 4 − 2 = 2.
4. Read the answer: 502 − 267 = 235.
5. Check by adding the difference back: 235 + 267 = 502.

Use the step-by-step player under the result to watch each borrow happen on your own numbers. It also handles borrowing across several zeros, such as 1,000 − 1 = 999.

Line up the decimal points and add zeros so both numbers have the same number of decimal places, then subtract column by column as usual. For 12.5 − 3.75, write 12.50 − 3.75 = 8.75. The decimal point in the answer sits directly under the points above.

If you subtract a bigger number from a smaller one, the difference is negative. 3 − 10 = −7: start at 3 on the number line and move 10 steps to the left, passing zero. To work it out by hand, subtract the smaller from the larger (10 − 3 = 7) and put a minus sign in front.

• Not commutative: 10 − 4 = 6 but 4 − 10 = −6. The order changes the answer.
• Not associative: (10 − 4) − 3 = 3 but 10 − (4 − 3) = 9.
• Subtracting zero changes nothing: 25 − 0 = 25.
• A number minus itself is zero: 25 − 25 = 0.
• Subtraction is adding the opposite: a − b = a + (−b). So 10 − 4 is the same as 10 + (−4).

• 845 − 327 = 518 (the units borrow once: 15 − 7 = 8, then 3 − 2 = 1, then 8 − 3 = 5).
• 1,000 − 347 = 653 (subtract from 999 and add 1 back, or borrow across the zeros).
• 12.5 − 3.75 = 8.75.
• 0.9 − 0.35 = 0.55.
• (−4) − 6 = −10 (start at −4 and move 6 more to the left).
• 5 − (−3) = 8 (subtracting a negative adds).

• Count up: to find 83 − 79, count up from 79 to 83, which is 4 steps.
• Round and adjust: 83 − 29 = 83 − 30 + 1 = 54.
• Subtract from a round number: 1,000 − 347. Take each digit from 9 (6, 5, 2) and the last from 10 (3): 653.
• Split the number: 94 − 37 = 94 − 30 − 7 = 64 − 7 = 57.

Subtraction gives you the change from a purchase, how much is left in a budget, the age gap between two people, the change in temperature, the time between two events, and the profit after costs. Whenever you ask "how much more" or "how much is left", you subtract.