<em>Colin ties 5 groups of balloons to the fence. There are 3 orange balloons, 2 blue balloons, and 4 green balloons in each group. How many balloons does Colin use?</em>
We know that in each group we have:
3 orange.
2 blue.
4 green.
So, we have 9 balloons per group and 5 groups. We have to multiply 9 by 5 groups, we have 45 balloons in total.