GCF & LCM: Biggest Shared Factor, Smallest Shared Multiple
I can find the Greatest Common Factor and Least Common Multiple of two numbers.
📘 Word Bank + Sentence Frames
factor (divides evenly)multiple (counting by)GCFLCMcommon = shared
- GCF = the biggest factor both numbers share.
- LCM = the smallest multiple both numbers share.
- Frame: "The GCF of ____ and ____ is ____ because it is the biggest number in both factor lists."
👀 See It: A Worked Example
Find the GCF of 12 and 18. List the factors of each:
12 → 1, 2, 3, 6, 12
18 → 1, 2, 3, 6, 9, 18
18 → 1, 2, 3, 6, 9, 18
Both lists share 1, 2, 3, and 6. The biggest shared factor is 6, so GCF(12, 18) = 6.
✏️ Your Turn
0 of 3 checks complete
1. Factors of 8: 1, 2, 4, 8. Factors of 12: 1, 2, 3, 4, 6, 12. What is the GCF?
2. Multiples of 3: 3, 6, 9, 12… Multiples of 4: 4, 8, 12, 16… What is the LCM?
3. The GCF is the BIGGEST shared… ?
💬 Explain Your Thinking
Explain the difference between GCF and LCM:
"GCF means blank (biggest shared factor). LCM means blank (smallest shared multiple)."