## Adding, Subtracting, Multiplying, and Dividing Decimals

## Overview: In this lesson you will learn the proper way to add, subtract, multiply, and divide decimals and problems with numbers and decimals. This lesson will show you how to line up your decimals and get the correct answer. This lesson also includes example problems

Step one: Line up the decimals by rewriting the problem vertically.

Step two: Add the decimal by starting on the right hand side, remember to carry your numbers.

Step three: (varied) For adding and subtracting, you bring the decimal directly down, (that's why it's so important to stay neat.) For multiplying, you count over the place of the decimal then in your answer move the decimal over that same number of places (an example will be shown in the multiplication section of this page.) For dividing, you bring up the decimal from the dividend (number inside of the bar) directly up.

Step two: Add the decimal by starting on the right hand side, remember to carry your numbers.

Step three: (varied) For adding and subtracting, you bring the decimal directly down, (that's why it's so important to stay neat.) For multiplying, you count over the place of the decimal then in your answer move the decimal over that same number of places (an example will be shown in the multiplication section of this page.) For dividing, you bring up the decimal from the dividend (number inside of the bar) directly up.

## Adding Decimals

TIP: For some people, a good way to learn how to use decimals is
to think of them as money...just don't put the dollar sign!

Adding Decimals:

25.753+12.365=? Always remember to set up the problem vertically and ALWAYS ALWAYS ALWAYS SHOW YOUR WORK!

First you need to line up the decimals to help you keep your answers in order. (Shown in Pink)

Then you add as if this is a normal problem, ignore the decimals. (Shown in Neon Green)

Then (as long as the decimals are lined up,) you bring the decimal directly down. (Shown in Blue)

In this problem the decimal can easily be brought down

Remember to carry your numbers (orange) and stay neat, don't make it hard on yourself by not being able to read your own work!

Adding Decimals:

25.753+12.365=? Always remember to set up the problem vertically and ALWAYS ALWAYS ALWAYS SHOW YOUR WORK!

First you need to line up the decimals to help you keep your answers in order. (Shown in Pink)

Then you add as if this is a normal problem, ignore the decimals. (Shown in Neon Green)

Then (as long as the decimals are lined up,) you bring the decimal directly down. (Shown in Blue)

In this problem the decimal can easily be brought down

Remember to carry your numbers (orange) and stay neat, don't make it hard on yourself by not being able to read your own work!

## Subtracting Decimals

Just like addition, you will set up the problem vertically and
also SHOW YOUR WORK!

First, you need to line up the decimals to help you stay neat and get the correct answer. (Shown in Pink)

Then you subtract the problem ignoring the decimals. (Shown in Neon Green)

Next, ( as long as the decimals are lined up,) you bring the decimal directly down (Shown in Blue)

First, you need to line up the decimals to help you stay neat and get the correct answer. (Shown in Pink)

Then you subtract the problem ignoring the decimals. (Shown in Neon Green)

Next, ( as long as the decimals are lined up,) you bring the decimal directly down (Shown in Blue)

## Multiplying decimals

Just like addition and subtraction, you will set up the problem vertically and SHOW YOUR WORK!

For multiplication, you DO NOT have to line up the decimals

Multiply the problem as if it was a normal problem, ignore the decimals

You count how many spaces each decimal is over. (Shown in Blue)

For multiplication, you DO NOT have to line up the decimals

Multiply the problem as if it was a normal problem, ignore the decimals

You count how many spaces each decimal is over. (Shown in Blue)

## Dividing Decimals

Move the decimal over until the divider is a positive number with no decimals.
You new problem will be 123/23

Problem: 12.3/ 3

Step one: Move over the decimal in the dividend until number is positive

Step two: Divide the problem

Step three: Bring the decimal DIRECTLY up from the dividend.

Example: Move the 3 over in 12.3 to make 123 the you have to do the same to the divider so the 3 would be 30, your new problem is 123 divided by 30, remember, to still put the decimal up and when you have leftovers don't use remainders! Add a zero on the right side of the decimal

Learning how to divide decimals is usually the hardest to learn out of the types of decimal problems for most people. Just remember that you to not put a remainder on the end of your problem, you can always add a 0 onto the end of the problem and keep it going until the problem comes out even, also, your teacher will most likely tell you if he or she would like you to go over to the tenths, hundredths, thousandths, or more for your final problem.

Step one: Move over the decimal in the dividend until number is positive

Step two: Divide the problem

Step three: Bring the decimal DIRECTLY up from the dividend.

Example: Move the 3 over in 12.3 to make 123 the you have to do the same to the divider so the 3 would be 30, your new problem is 123 divided by 30, remember, to still put the decimal up and when you have leftovers don't use remainders! Add a zero on the right side of the decimal

Learning how to divide decimals is usually the hardest to learn out of the types of decimal problems for most people. Just remember that you to not put a remainder on the end of your problem, you can always add a 0 onto the end of the problem and keep it going until the problem comes out even, also, your teacher will most likely tell you if he or she would like you to go over to the tenths, hundredths, thousandths, or more for your final problem.