Number

Square numbers

These are special numbers. Here you see a square, it is two long and two high. The total number of squares inside is 4

We say it is a two by two square. We find the number of squares inside by multiplying the length by the height.

So 2 X 2 = 4. Instead of writing 2 X 2 we could write 22. This means 2 times by itself. (We say two squared).

 

The next square number is 9. (Do you know why?)

To make a square of 9 we have to multiply 3 by itself or write 3 X 3 or 32.(we say three squared)

Here is a drawing of 32 (Three squared)


Look how many small squares it contains (9).

So we have seen that both 4 and 9 are square numbers We found these by: multiplying 2 by 2 to get 4 or 22 =4

Multiplying 3 by 3 to get 9 or 32 =9

(You will see this again in finding Areas)

What is the answer to 12

Check your answer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer = 1 because 1 x 1 = 1 or 12 =1



Remember each square number must form a square

Can you find the the square numbers up to 100?

42 =             52 =             62 =             72 =             82 =             92 =             102 =

 

Check your answers

 

 

 

 

 

 

 

 

 

 

 

 

 

42 =16                   52 =25                   62 =36                   72 =49                   82 =64

92 =81                   102 =100    

How did you do?

Remember and learn to recognise the square numbers: 1, 4, 9, 16, 25, 36, 49, 64, 81,100

The numbers that you have to multiply to get the square numbers are called the square root.

This is the sign for the square root √.


For example the square root of 100 is 10 written as √100 = 10

 

Can you find the square roots of the following numbers?

√81 =         √49 =         √4 =           √64 =         √36 =

√16 =         √1 =           √25 =        

Which one did I miss out?

Check your answers

 

 

 

 

 

 

√81 =9       √49 =7       √4 = 2        √64 = 8      √36 = 6

√16 = 4      √1 = 1        √25 = 5     

Which one did I miss out?

√9 = 3  

To finish, to multiply a number by itself, means to square it.

The opposite (or the inverse) of squaring a number is to find its square root.

Well that wasn't too hard was it?

Good luck!

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