Answer:
Explanation:
For 30: 1,2,3,5,6,10,15,30
For 21: 1,3,7,21
For 56: 1,2,4,7,8,14,28,56
Because you always go times it by the number. Example is: 1 is always in the factors (Doesn't matter if it's the least common factor or whatever) because whatever you times by 1, it's that answer. Or you can look at the answer, (I'm doing the 30) First, find the middle which is 5 and 6. You times 5 and 6 and it will give you 30. People call it a rainbow, 5x6=30, 3x10=30, 2x15=30, and 1x30=30.
I hope this helps