NSF - Decimal Fluency Lesson

Decimal Fluency

Addition and Subtraction with Decimal Numbers

Finding the sum of decimal numbers can be accomplished by writing the decimal numbers one under the other and keeping the decimal points in a line vertically. Using this method, the whole numbers will be added to whole numbers, tenths added to tenths, hundredths to hundredths, and so on. The decimal point in the sum (the answer) is in the same line with the decimal points in the numbers that were added.  

For example, to add 2.357 + 6.14, we write:

Finding the difference of decimal numbers works exactly the same way as finding the sum of decimal numbers by writing the decimal numbers one under the other and keeping the decimal points in a line vertically.

Multiplication with Decimal Numbers

The product of decimal numbers is found in the same manner as whole numbers are multiplied with the added concern of the correct placement of the decimal point in the product. Look at the examples below shown in fraction form and decimal form to illustrate how the decimal point is to be placed in the product.

Division with Decimal Numbers

The process of division with decimal numbers is, in effect, the same as division with whole numbers with the added concern of where to place the decimal point in the quotient.

To divide decimal numbers first move the decimal point in the divisor to the right so that the divisor is a whole number.

Next, move the decimal point in the dividend the same number of places to the right.

Then place the decimal point in the quotient directly above the new decimal point in the dividend.

Finally divide just as with whole numbers.

Watch the videos below for some more examples.  Click on the image to start the videos.

Dividing Fractions and Decimal Fluency Assignment

Download the "Dividing Fractions and Decimal Fluency Assignment" by clicking here. Be sure to work all of the practice problems on the paper. You will use these problems and solutions when you complete the "Making Relevant Connections through Number System Fluency Homework Quiz 2." Remember you can always go back and review the lessons and videos for more help. Links to an external site.

Once you've done the practice work, you can click here for the first answer key to check it. Links to an external site.

Here's the second page of the answer key. Links to an external site.

Here's the third page of the answer key. Links to an external site.

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