Now we know one percent of the dinosaur's length we can just multiply that by 12 to find 12%. Then we'll know how long the little one is. 3cm multiplied by 12 is 36cm. The trick is to keep it ...

Practise Rachel's method for finding percentages and you'll know if you've got a real bargain on your hands in no time. Check out another double-digit multiplication trick with Rachel's maths hack ...