In this activity, we will learn a crafty trick to add up consecutive numbers.

Eddie has spotted that if you steal one from the last number and give it to the first number, he now has three identical numbers to add up.

Example

Add  together 11 + 12 + 13

Using Eddie's trick, this becomes 12 + 12 + 12 which is just 3 x 12 = 36

Eddie also notices that to add together five consecutive numbers, he can use a similar trick by stealing two from the fifth number and giving it to the first number, stealing one from the fourth number and giving it to the second number.  This gives him five identical numbers to add up.

Example

Add  together 6 + 7 + 8 + 9 + 10 becomes 8 + 8 + 8 + 8 + 8 which is just 5 x 8 = 40

Clever stuff, eh!

In this activity, we will be looking for tricks to help us to solve mental maths calculations.

Let's get started!