Friday, October 4, 2013

Subtracting decimals

Subtracting decimals is similar to subtracting whole numbers I strongly encourage you to review subtraction of whole numbers before learning this lesson.

Before subtracting, line up the decimal points. It is also important to use 0 as a placeholder when a place value is blank

Look at the following subtractions problems. they are fairly easy to subtract.

Look at the following subtractions problems. they are fairly easy to subtract.

subtracting-decimals-image

in the first problem on the left (0.5 - 0.2), just remove 2 tenths from 5 tenths to get 3 tenths. Then 0 take away 0 is 0. Finally write down your decimal point.

Now look at the following problem:

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Since you cannot remove 8 hundredths from 5 hundredths, you need to take 1 tenth from 4 tenths and add that to 5 hundredths to get 15 hundredths.

subtracting-decimals-image

Then, 15 hundredths - 8 hundredths = 7 hundredths

3 tenths - 2 tenths = 1 tenth

Finally, 0 - 0 = 0 and put your decimal point.

The following problem shows the importance of using 0 as a placeholder before subtracting:

subtracting-decimals-image

Using 0 as a placeholder, we get:

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Again, we cannot remove 5 hundredths from 0 hundredth, so we will borrow 1 tenth( 1 tenth = 10 hundredths) from 5 tenths and add that to 0 hundredth.

We get:

subtracting-decimals-image

Study too the following example carefully:

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Use 0 as placeholders

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Then, do the following:

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Study this last example too carefully:

subtracting-decimals-image

Step 1:

subtracting-decimals-image

Step 2:

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Step 3:

subtracting-decimals-image

subtracting-decimals-image

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