How do you add

0.50 + 0.25?

In this lesson you will learn how to add decimals by using a

number line.

Let’s ReviewLet’s Review

1212

14341434

0 1 2

Let’s ReviewLet’s Review

0.5 = =

0.25 = = 0.75 = =

0.1 =

Let’s ReviewA Common Mistake

0 1 2

l l l l l l l l l l l0 1

This number line shows fourths and halves

This number line shows tenths

Let’s ReviewCore Lesson

I have 1.5 ounces of peanut butter left in a jar. I combine it with another jar that has 2.25 ounces of peanut butter. How much peanut

butter do I have now?

1.5 + 2.25

Let’s ReviewCore Lesson

1.5 + 2.25?

How do you add

Let’s ReviewCore Lesson

1.5 + 2.25

Smart estimate:1.5 = 1.50

= +2.25 +2.25

3.75

Let’s ReviewCore Lesson

1.5 + 2.25

0.5 + 0.25

42 30 1

+1 +2 = 3.75

This matches our smart estimate

In this lesson you have learned how to add decimals by using a

number line.

Let’s ReviewGuided Practice

You walk 1.25 miles to your friend’s house. Then you both walk to the park 0.5 miles away. How far do you walk altogether?

Let’s ReviewExtension Activities

Use a number line to show the addition of three common decimals.

Let’s ReviewExtension Activities

Explain why you can add the numbers in any order and get the same answer. Back up your answer with at least 2 different number line drawings.

Let’s ReviewExtension Activities

Your recipe calls for cup of milk, cup of water, and 1 cups of apple juice. Change these fractions to decimals and use a number line to show how much liquid this is altogether.

Let’s ReviewQuick Quiz

Use a number line to find the answer to these problems:0.5 + 1.25 =

2.25 + 1.75

A. 1.50 B. 1.75 C. 1.3

A. 4.25 B. 3.75 C. 4