Line up the numbers in your operation so that the decimal points align in a column, then draw a line beneath them. For example, when you subtract 3.47 from 5.523, you would write:
5.523
-3.47
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Add zeroes to the numbers so that each one has the same number of digits after the decimal point. This helps you keep your place in the equation. For example: 5..523 - 3.47 becomes:
5.523
-3.470
---------
Begin with the far right column of numbers and subtract the bottom number from the top number. In the example you would subtract zero from the "3" above it, then write the result, "3," beneath those numbers. For example:
5.523
-3.470
---------
3
Add 10, then subtract 1 from the number to the left when the number on top is smaller than the number on the bottom. In the example, the 7 is too large to subtract from the two. Add 10 to the two to get 12, then subtract 1 from the 5 to the left of the 2. Now subtract the 7 from the 12 to get 5. This leaves you with:
5.423
-3.470
---------
53
Continue subtracting the columns until you have subtracted the numbers in the far left column. This leaves you with:
5.423
-3.470
---------
2 053
Add a decimal point to the answer so that it aligns with the decimal points above. This leaves you with the answer 2.053. For example:
5.423
-3.470
---------
2.053