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Chapter 4—Decimals

4-4 Adding Decimals

When you complete the work for this section, you should be able to:
  • Explain how to align decimal points when adding decimal numbers.
  • Demonstrate an ability to add decimal numbers without making errors.

The procedures for adding decimals is nearly the same as for adding integers. The only difference is that you must align the decimal points in order to make sure you are adding the same place valuesones to ones, tenths to tenths, hundreds to hundreds, hundredths to hundredths, and so on.

Procedure

Step 1: Write the decimal values in vertical form, aligning the decimal points.

fig040301.gif (1232 bytes)

Note: Aligning the decimal points automatically aligns the place values—ones with ones, tenths with tenths, and hundredths with hundredths.

Step 2: Add the values in the same way you would add any column of numbers, placing the decimal point directly in line with the decimal points in the addends.

fig040302.gif (1288 bytes)

Example 1

Problem

1.2 + 4.3 = _____

Procedure
  1. Write the decimal values in vertical form, aligning the decimal points vertically.

      1.2
  + 4.3

  1. Add the columns, placing the decimal point directly in line with the decimal points in the addends.
     1.2
  + 4.3
     5.5
Solution

1.2 + 4.3 = 5.5

Example 2

Problem

4.28 + 1.6 = _____

Procedure
  1. Write the decimal values in vertical form, aligning the decimal points vertically.

     4.28
  + 1.6

  1. Add the columns, placing the decimal point directly in line with the decimal points in the addends.
     4.28
  + 1.6
     5.88
Solution

4.28 + 1.6 = 5.88

Example 3

Problem

Add 0.26 and 12.482

Procedure
  1. Write the decimal values in vertical form, aligning the decimal points vertically.

      0.26
  +12.482

  1. Add the columns, placing the decimal point directly in line with the decimal points in the addends.
      0.26
  +12.482
    12 .742
Solution

 

0.26 + 12.482 = 12.742

Examples and Exercises

Adding Decimals

Use these interactive examples and exercises to strengthen your understanding and build your skills:

David L. Heiserman, Editor

Copyright   SweetHaven Publishing Services
All Rights Reserved

Revised: June 06, 2015