Grade 1

The Human Knowledge Project

Unit 6 — Adding Numbers

Welcome back!

Today we will become even stronger mathematicians.

We will learn more about addition.

Addition means putting groups together to find the total.

We use addition every day.

What Is Addition?

Imagine you have:

3 apples

Then someone gives you:

2 more apples.

Now you have:

5 apples.

We write this as:

3 + 2 = 5

The plus sign (+) means "put together."

The equals sign (=) means "has the same value as."

Adding with Pictures

Pictures can help us understand addition.

⭐⭐⭐

+

⭐⭐

=

⭐⭐⭐⭐⭐

Drawing pictures helps us see how numbers combine.

Number Sentences

A math problem written with numbers is called a number sentence.

Examples:

4 + 3 = 7

6 + 2 = 8

5 + 5 = 10

Each number sentence tells a complete mathematical idea.

Adding on a Number Line

A number line helps us count forward.

Start at 4.

Move forward 3 spaces.

You land on 7.

Number lines help us see addition as moving forward.

Finding Patterns

Addition has many patterns.

Look carefully.

1 + 1 = 2

2 + 2 = 4

3 + 3 = 6

4 + 4 = 8

5 + 5 = 10

Can you predict what comes next?

Looking for patterns helps mathematicians solve problems.

Word Problems

Addition helps solve real-life problems.

Example:

Emma has 6 crayons.

Her friend gives her 3 more crayons.

How many crayons does Emma have now?

6 + 3 = 9

Emma now has 9 crayons.

Activity

Find small objects around you.

You might use:

Make two small groups.

Count each group.

Now put them together.

Write the number sentence.

Practice

Solve these problems.

2 + 5 = _____

7 + 1 = _____

4 + 4 = _____

9 + 0 = _____

3 + 6 = _____

Can you make two addition problems of your own?

Review

Today you learned:

Every time you practice, addition becomes easier.

Looking Ahead

Next we will learn about subtraction.

You will discover:

Addition and subtraction are closely connected.