# Long subtraction

It is very simple to make a long subtraction of two numbers by hand.

Let’s take a look at the subtraction problem 9122-4977.

| First the subtraction problem 9122-4977 is set up. It's important that the digits are placed correctly, so that the ones, the tens, the hundreds, the thousands etc. of the two numbers are right above each other. |

| Then we take a look at the first column, the column of the ones. We calculate 2-7, the result of which is -5. Since we get a negative number, we must take 1 from the column of the tens and carry it over to the column of the ones, where it becomes 10, because 1 of the tens is equal to 10 of the ones. We can then calculate 10+2-7=5. We write 5 in the result and 1 at the bottom of the column of the tens, so we do not forget that 1 was taken from there. |

| Now we take a look at the column of the tens. We calculate 2-7-1, the result of which is -6. Since we get a negative number, we must take 1 from the column of the hundreds and carry it over to the column of the tens, where it becomes 10, because 1 of the hundreds is equal to 10 of the tens. We calculate 10-1+2-7=4. We write 4 in the result and 1 at the bottom of the column of the hundreds, so we do not forget that 1 was taken from there. |

| Now we take a look at the column of the hundreds. We calculate 1-9-1, the result of which is -9. Since we get a negative number, we must take 1 from the column of the thousands and carry it over to the column of the hundreds, where it becomes 10, because 1 of the thousands is equal to 10 of the hundreds. We calculate 10-1+1-9=1. We write 1 in the result and 1 above the column of the thousands, so we do not forget that 1 was taken from there. |

| Now we take a look at the column of the thousands. We calculate -1+9-4, the result of which is 4. We write 4 in the result. |

**The result is 9122-4977=4145.**

## Long subtraction

Please enter the two numbers you want to subtract from each other.## Decimal numbers

When you subtract decimal numbers from each other, it’s important that the decimal points of the two numbers are right above each other.

Had the example above been with the decimal numbers 91,22 and 49,77 instead, the subtraction would have been set up like this:

9 | 1 | . | 2 | 2 | |

- | 4 | 9 | . | 7 | 7 |

4 | 1 | . | 4 | 5 |

## If the number you are subtracting is greater than the number you are subtracting from

If the number you are subtracting is greater than the number you are subtracting from, you will get a negative number as result. When that’s the case, the best way to perform the long subtraction is to swap the two numbers, so that the smallest number is subtracted from the greater one and then put a minus sign in front of the result.

Example:

13 - 17 = ?

We calculate 17 – 13 instead:

17 - 13 = 4

Now we must remember to put a minus sign in front of the result.

Therefore 13 - 17 = -4