Decimal Addition

Decimal Addition:

To add decimal numbers:

  • Write the numbers vertically, Lining up the decimal points in the numbers.
  • Pad zeros to numbers to cause each number to have the same number of decimal digits.
  • Copy the decimal point straight down into the answer.  
  • Add by columns as if you were adding whole numbers.

The following are examples of adding decimals.

Adding Decimals
Given decimals to add ... Write the numbers vertically, lining up the decimal points. Pad extra zeros after the decimal point.  Make each number have the same number of digits after the decimal point. Copy the decimal point straight down into the answer. Add the columns as if they were whole numbers.
7.4+ 7.33
7.4-
+ 7.33
7.40
+ 7.33
7.40
+ 7.33
.--
7.40
+ 7.33
14.73
6.87 + 9.4
6.87
+9.4-
6.87
+9.40
6.87
+9.40
.--
6.87
+9.40
16.27
0.34 + 0.4
0.34
+0.4-
0.34
+0.40
0.34
+0.40
.--
0.34
+0.40
0.74
0.61 + 0.615
0.61-
+ 0.615
0.610
+0.615
0.610
+0.615
.--
0.610
+0.615
1.225

Check Your Understanding

If you were to add the following pairs of numbers, which number of the pair would you "pad" with zeros....

  1. 2.04 or 2.4
  2. 32.5 or 3.23
  3. 0.24 or 0.5

Test your understanding of decimal addition:

  1. Enter two decimals between 0 and 999.9999.
  2. Figure out what you believe the answer should be.
  3. Click the button "Check" and check your answer.
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