Start by measuring the overall size of the wall, height by the width.
So 2500mm x 5000mm = 12.50 square meters or m2
Next the window, height by the width again. So 1000mm x 1500mm = 1.50 m2
Now the door, height by width again. So 1960mm x 760mm = 1.489600 m2. Round this off as 1.5 m2 to make it easier.
So we've got to take away 1.5 m2 for the window and 1.5 m2 for the door equalling 3 m2.
2.5 Square meters minus 3 square meters = 9.5 m2.
Now we add 10% extra to allow for cuts and waste. 9.5 m2 + 10 % = 10.45 m2.
Total amount of tiles needed is 10.45 m2.
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