It’s Numberland’s Great Bug Race! One to Four's pet bugs are racing on special tracks, but can they follow the perimeter? Numberblocks are on hand to help your little one learn about numbers and start ...

To calculate the perimeter of a shape, like this window, you can add the length of all the sides together. 100cm + 120cm + 100cm +120cm = 440cm Or, you can multiply the length and width by 2.