What are numbers in a multiplication problem called?

The related link that I posted sums it up pretty good, but here it is: Multiplicand X Multiplier = Product. From the Commutative Property of multiplication, you can take A X B and B X A and get the same answer, so many times, people just refer to them as factors: Factor X Factor = Product.

The concept of a multiplier is important when teaching multiplication. If you have 4 x 5, the multiplier is 5, so you would perform 4 + 4 + 4 + 4 + 4 = 20 (add 4, five times), if you do 5 x 4, then it is 5 + 5 + 5 + 5 = 20. The multiplier tells you how many times to take the multiplicand as an addend and the resulting sum is the answer (product) to the multiplication problem.