Addition of Decimals

We can use models to add decimals

Steps to follow to add two decimals (0.50 + 0.35):

Step 1: Model 0.50
Show 0.50 by coloring 50 squares of the 10-by-10 grid as blue.

Step 2: Model 0.35
Show 0.35 by coloring 35 squares of the 10-by-10 grid as yellow.

Step 3: Count the total number of colored squares
Total number of colored squares = 50 + 35 = 85
85 squares = 0.85

To add two decimals, line up the decimal points. Start with tenths. Add each place. Regroup if necessary

For example, add 1.7 and 1.5
7 tenths + 5 tenths = 12 tenths; 12 tenths = 1 one + 2 tenths

To add the dollar amounts, line up the decimal points. Add as we would whole numbers. Regroup if necessary. Place the decimal point and the dollar sign in the sum