Addition

What is Addition?

Imagine you have some toys, and then you get more. The total number of toys you have has increased. This process of joining groups together is called addition!
Let's try it. If you have 2 red blocks and your friend gives you 1 blue block, how many blocks do you have now?

$\quad$ and $\quad$

Let's count them all together: One, two, three. You have 3 blocks in total!

Definition Addition

Addition is joining groups together to find the total, called sum.
In mathematics, we use symbols to write this down:

The plus sign ($+$) means to add.
The equals sign ($=$) shows that what is on one side is the same amount as what is on the other side.

We can represent "$\textcolor{colordef}{\text{two }}\text{plus}\textcolor{colorprop}{\text{ one}}\text{ equals }\textcolor{olive}{\text{three}}$" in many ways:

With numbers: $$\textcolor{colordef}{2} + \textcolor{colorprop}{1} = \textcolor{olive}{3}$$
With cubes: $+$ $=$
With fingers: $+$ $=$

How to Add

Method Counting All

The first strategy to learn addition is called "Counting All." This means we combine our groups and then count every single item from the beginning to find the total.
Let's solve: $3 + 2 = ?$

Step 1: Show the first number. Hold up 3 fingers on one hand.
Step 2: Show the second number. Hold up 2 fingers on your other hand.
Step 3: Count all the fingers that are up. Point to each one as you count: "One, two, three, four, five!"

The total is 5. $3+ 2 = 5$

$+$

$=$