How many ways are there to put 5 balls with colors red, orange, yellow, green, and blue into 3 indistinguishable bowls? a case by case approach is a good strategy for this type of problem.
(this question has been answered on the site, but the person who answered that question treated the bowls as distiguishable when they need to be indistiguishable. you! )

Do you mean conversion factor?

The skating rink rented 872 pairs of skates during april and may.why? : if the skating rink rented three times the pair of skates in april during may, they rented 654 skates. 218 x 3 = 654then, if they want to know how many they rented during both april and may, then you just add 654 (may) and 218 (april) to give you 872 pairs of skates for both months.654 + 218 = 872hope this !