Answer: 64
Explanation:
You want to use multiples of both numbers in order to solve the equation. You see that the balloons come in packs of 8 and 21 so we are going to be calculating the multiples of 8 and 21 until we reach the least common multiple.
8: 8,26,24,32,40,48,56,64
21: 21,42,64
As you can see it took a lot longer to get to 64 from 8 but both numbers have 64 as multiples. Therefore 64 is the answer. It is also the first common multiple that we discovered so that solidifies that it’s the answer.
Hope this helps :)