Array
The town hall is 3 windows tall and is 8 windows across. That is a 3 by 8 array.
Click
to see a 3 by 8 array!
Let’s Learn!
Why do we build arrays?
Goal:
Goal:
Think About It!
Goal: Can you build an array?
The windows on the town hall look like an array. An array puts items in rows and columns. Then we can see the groups and how many are in each!
We will use the array to create a repeated addition sentence and a multiplication sentence. Both will get us the correct answer. A repeated addition sentence adds the same addend over and over. A multiplication sentence multiplies two factors.
Add
This is a 3 by 8 array.
We need to write a repeated addition sentence.
Question:
How many addends do we need?
There are 3 rows. We need 3 addends.
Question:
What is the repeated addend?
There are 8 dots in each row. 8 is the repeated addend.
Multiply
8 + 8 + 8 = ? is the repeated addition sentence.
We need to write a multiplication sentence.
Question:
What is the first factor?
There are 3 rows. This is the number of groups. 3 is the first factor.
Question:
What is the second factor?
There are 8 dots in each row. This is the number in each group. 8 is the second factor.
Total Number
3 x 8 = ? is the multiplication sentence.
How many windows are on the town hall? We need to find
the total number for each sentence. Click
to see!
The town hall has 24 windows!
We build arrays to add and multiply. The array helps us find the total number!