Norma and Rene are serving cupcakes at a school party. If they arrange the cupcakes in groups of 2.3.4.5. or 6 they have exactly one cupcake left over. what is the smallest number of cupcakes they could have?

We are given that there are 5 groups which are:

group of 2

group of 3

group of 4

group of 5

group of 6

and 1 left over

So the smallest number of cupcakes would simply be the sum of all:

smallest number of cupcakes = 2 + 3 + 4 + 5 + 6 + 1

smallest number of cupcakes = 21