GCF-LCM Homework - page 2

Name ______________

Find the least common multiple (LCM) of these pairs of numbers:
1. Write out the multiples of both numbers to their right.
2. Find the smallest one that appears in both lists and circle it.


1).
Multiples of 15:____________________

Multiples of 25:____________________

    LCM = _____		 2).
Multiples of 14:____________________

Multiples of 28:____________________

    LCM = _____
3).
Multiples of 40:____________________

Multiples of 15:_____________________

    LCM = _____		 4).
Multiples of 48:____________________

Multiples of 32:____________________

    LCM = _____
5).
Multiples of 20:____________________

Multiples of 25:____________________

    LCM = _____		 6).
Multiples of 8:____________________

Multiples of 28:____________________

    LCM = _____
Find the greatest common factor (GCF ) of these pairs of numbers by using the GCF formula:

GCF(a,b) = (a x b) / LCM(a,b)

The pairs of numbers below are the same as above, so you can use the LCMs you found to find their GCFs:

7).
GCF(15,25) = (15 x 25) / _____ = _____		 8).
GCF(14,28) = _______________ = _____
9).
GCF(40,15) = _______________ = _____		 10).
GCF(48,32) = _______________ = _____
11).
GCF(20,25) = _______________ = _____		 12).
GCF(8,28) = _______________ = _____