Practice Set · Part 1
Find Factors and Multiples
Pick up where we left off
Where we left off
Our goal: With my small group, I can find the greatest common factor and the least common multiple of two numbers, and use each to solve a real problem — one step at a time, with support.
The big idea: Use the GCF to split amounts into equal groups. Use the LCM to find when repeating events line up again.
Model to copy — Example 1 · Greatest common factor (GCF)
- A store has 48 pencils and 36 notebooks. The manager makes combo packs. All packs must be the same, with nothing left over. What is the greatest number of packs?
- List the factors of 48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
- List the factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
- Circle the factors in both lists: 1, 2, 3, 4, 6, 12
- Choose the greatest common factor: GCF = 12; 48 ÷ 12 = 4; 36 ÷ 12 = 3
- The GCF is 12. The manager can make 12 packs, each with 4 pencils and 3 notebooks.
- Ayasha has painting class every 8 weeks and pottery class every 6 weeks. Both classes are this week. In how many weeks will both fall in the same week again?
- List the multiples of 8: 8, 16, 24, 32, …
- List the multiples of 6: 6, 12, 18, 24, …
- Find the least number in both lists: LCM = 24
- The LCM is 24. Both classes fall in the same week again in 24 weeks.
Start here
You did these with your group. Now do them on your own — the model above is yours to copy.
- 1
Same stepsFinish what the group started. Use the model above, step for step.
Let's do one together: Use prime factors to find the GCF of 48 and 36. Use the factor tree. Write 48 as a product of primes. (2 × 2 × 2 × 2 × 3) Write 36 as a product of primes. (2 × 2 × 3 × 3) Which primes do both numbers share? (Two 2s and one 3.) Multiply the shared primes. What is the GCF? (2 × 2 × 3 = 12)My first step is ___ , because the problem asks for ___ .
Show your work - 2
Warm restartWhich expression is equivalent to 5x + 2x?
- A7x
- B7x²
- C10x
- D52x
- 3
Warm restartAre 3(n + 2) and 3n + 6 equivalent? Test with n = 4.
- ANo — one is 18 and one is 14
- BYes — both equal 18
- CYes, but only when n = 0
- DYou cannot test with a number
- 4
Warm restartSimplify 6a + 4 − 2a.
- A2a + 4
- B4a + 4
- C4a
- D8a
Practice Set · Part 2
Find Factors and Multiples
Keep going
You answered these out loud. Now write them.
Answer, then say how you know — the reason is the part that counts.
- 5
Think it throughWhat is the GCF of 48 and 36?
- A4
- B6
- C12
- D144
Why is that the answer?
I chose ___ because ___ .
- 6
Think it throughWhat is the LCM of 6 and 8?
- A2
- B14
- C24
- D48
How do you know?
I chose ___ because ___ .
- 7
Think it throughA problem asks when two repeating schedules meet again. Which do you use?
- AThe least common multiple
- BThe greatest common factor
- CEither one works
- DNeither — you list factors
Explain your thinking.
I chose ___ because ___ .
- 8
Back to the modelBoth problems say “common.” How do you decide whether a problem wants the GCF or the LCM?
If the problem ___ something into equal groups, I use the ___. If it asks when things ___ again, I use the ___.
Sort it again — on paper this time
Write the letter of the group each one belongs in.
- What is the largest number of identical combo packs?
- When will both classes fall in the same week again?
- How many equal groups can I split both stocks into?
- Hot dogs come in 10s and buns in 8s — when do they match?
- The answer is never bigger than either number
- The answer is never smaller than either number
Practice Set · Part 3
Find Factors and Multiples
Words and reasoning
Word bank · Banco de palabras
Use the words
Fill each blank with a word from the bank.
- A number that divides another exactly, with no remainder, is a ___.
- What you land on counting by a number are its ___.
- The largest number that divides both is their ___ ___ ___.
- The smallest number both numbers reach is their ___ ___ ___.
Explain the thinking
- 9
Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.
The mistake: A common mistake is reaching for the wrong tool: listing FACTORS for a problem about repeating cycles. - 10
Say moreHow did you find the factors that 24 and 36 share, and how did you decide which one is the GCF?
The common factors are ___.
- 11
Change one numberGo back to Part 1 and pick one problem you already solved. Change one number in it, then solve your new version. Show every step.
If ___ changed to ___ , then ___ .
Show your work
Practice Set · Part 4
Find Factors and Multiples
Show what you know
Last check
These two come from Lesson 6.6. If they are shaky, that is the lesson to revisit — not this one.
- 12
Show what you knowQuick check — you've got this: Two supply runs repeat every 6 weeks and every 8 weeks, and both happen this week. When will they next happen in the same week?
- AWeek 2, the greatest common factor of 6 and 8
- BWeek 14, because 6 + 8 = 14
- CWeek 24, the least common multiple of 6 and 8
- DWeek 48, because 6 × 8 = 48
Explain your choice.
I know it is ___ because ___ .
- 13
From Lesson 6.6Quick check — you've got this: Which expression is equivalent to 6n + 4 + 3n − 1?
- A9n + 3
- B9n + 5
- C18n + 4
- D63n
- 14
From Lesson 6.6Test it: what does each expression equal when h = 5?
- AA = 50 and B = 60
- BBoth equal 60
- CA = 60 and B = 55
- DBoth equal 90
Be honest — this tells your teacher what to do next
| I can… | Not yet | Getting there | Got it |
|---|---|---|---|
| I can find the greatest common factor and the least common multiple of two numbers, and use each to solve a real problem — one step at a time, with support. | |||
| I can explain why it works: Use the GCF to split amounts into equal groups. Use the LCM to find when repeating events line up again. | |||
| I can talk through each step out loud using a sentence frame and the lesson's key words. |
One question I want to ask my group next time