Arrays are a way of showing a number using rows and columns. You can find arrays everywhere you look.
For example: –
How many trays do you see? How would you work that out?
How many orange dots can you see?
You are going to be asked to find arrays for certain numbers. You will be using blocks or drawing pictures to do so in your math journal.
The equation you can write is :- 2 x 4 = 8 …………… or …………… 4 x 2 = 8
In your math journal you should record your investigation like this.
Every number can be multiplied by itself and one to give the right answer. Because every number has an array like the first one (1 x ?) we don’t need to do that one for any number. HOWEVER …. there are some numbers that only have that array! These are called PRIME NUMBERS – numbers that can only be made into an array of a long line, and that has factors of 1 and itself.
Using blocks, find all the arrays possible that would make the following numbers. Write an equation and draw the arrays into your math journal.
REMEMBER…YOU DO NOT NEED TO DO AN ARRAY FOR THE NUMBER TIMES 1!
12, 18, 20, 24, 28, 30, 32, 36, 40, 42, 44, 45, 48
Find all the prime numbers between 1 – 50 using arrays to prove your answer.