Grade 4 Decimals: Adding Decimals

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   9.9 + 1.5 = ?

   1. Line up the decimal points of 9.9 and 1.5.
   2. Add each column from right to left, regrouping when a column reaches 10.
   3. Bring the decimal point straight down into the answer.
   4. 9.9 + 1.5 = 11.4

   Answer: 11.4

2. Example 2

   Leo bought a puzzle for $9.23 and a yo-yo for $2.15. How many dollars did Leo spend in all?

   1. The story puts two amounts together ("in all"), so add.
   2. Line up the decimal points: 9.23 + 2.15. Think in hundredths: 923 + 215 = 1138 hundredths, which is 11.38.
   3. So the answer is $11.38.

   Answer: 11.38

3. Example 3

   Kai walked 3.4 km in the morning and 3.4 km in the afternoon. How many kilometers did Kai walk in all?

   1. The story puts two amounts together ("in all"), so add.
   2. Line up the decimal points: 3.4 + 3.4. Think in tenths: 34 + 34 = 68 tenths, which is 6.8.
   3. So the answer is 6.8 kilometers.

   Answer: 6.8