Question

There are four children. Each has 2 blue pens and 3 black pens. How many pens is that altogether? write this problem two different ways.

Answer 1

If there are 2 pens with 4 children , then total blue pens=2×4=8
 If there are 3 bllack pens with 4 children ,  then=3×4=12
so total  there are 12+8=20 pens!
Again
(2×4)+(3×4)
or,8+12
or,20