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Maths Thursday 4th February 2021

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Today we are going to continue to look at area.


Area is the amount of space taken up by the 2D shape.


 Our formula:

Length X Width


However as we found out yesterday this formula is not all that we need to work out the area of a shape. 


Lets have a look at a more complicated shape and see how we can work out the area of this shape. 


We want to work out the area of the purple shape. 



First we need to see if we can find rectangle within the shape. This was tricky but by adding the 2 red squares in I was able to create a rectangle. So now we can find out the area of this rectangle first.

Lets use our formula original formula:

Length X Width


Length = 3 cm

Width = 4 cm


Calculation = 3 cm X 4 cm 


 3 X 4 = 12 


3 cm X 4 cm = 12 cm²


Now we know the whole shape we can subtract the red area.


The red area is taking up 2 cm²


12 cm² - 2 cm² = 10 cm²


But now we have 2 extra boxes on the side of our original rectangle.

The area of these 2 boxes = 2 cm²


Now we need to add these onto our answer so far:


10 cm²2 cm² = 12 cm²


The area of the shape above is 

12 cm²


Lets now look at a different way to work out the area, when using a grid.



There is no definite rectangles we can use to make this easier. The easiest way to find the area of this shape would be to use the information given and count.


So we know each side is 1 cm in length and with. This means each box is 1cm²


Now we know that we can count the squares and this will be our answer.



The area of the shape is 13cm²


Using these examples to help you go onto Purple Mash and complete the 'Area' 2Do.