How to Add Decimals

Adding Decimals

There are many instances in which it’s important to be able to add decimals together. Say you have 80 cents, and then you earn 40 more cents, and you want to know how much money you have all together. You have to add those two decimals together, and adding decimals is a little more complicated than adding whole numbers.

What you have to do first is put the two numbers on top of each other like you always would in addition, but make sure the decimals are lined up with each other. Of course you’re going to draw the line underneath and put the addition symbol.

You go to the first column and you add those numbers together, so 0 plus 0 is 0, then 8 plus 4 is 12. You have the number 12, so the right digit (this one right here) you’re going to write down, and then the left digit is the one you’re going to carry over to the next column, so 1 plus 0, plus 0 is 1.

Then you carry the decimal just straight down, so you get 1 dollar and 20 cents. Now sometimes they’re a little more complicated. Say you have 0 point 83 of something, and then you have 0 point 98 of something. Again, you’re just going to line up the decimals with each other, and add them together, so you know the first column which is 8 plus 3 so that’s 11.

You put the right digit right there, then you carry the left digit over, so 1 plus 8 is 9, plus another 9 is 18, so you put the 8 there, carry the 1 over, (all the way down,1) and then of course you just carry the decimal place straight down, 1 point 81.

What you’re going to find is you’re going to come in contact with a lot of decimals that you’re going to have to add together, especially when you’re dealing with money. It’s important to be able to add those decimals very easily. Like I’ve emphasized a lot, make sure you always line the decimals up and then just carry that decimal place straight down.



by Mometrix Test Preparation | Last Updated: August 15, 2019