Greatest common factors and least common multiples.
GCF and LCM teaches sixth graders to find the greatest common factor and least common multiple of two numbers and use them to solve real problems, like making equal groups or working out when two schedules line up.
Math course · Grade 6
GCF and LCM · Learning goals
Find the greatest common factor and least common multiple of two numbers, and use them to solve real problems.
Why it matters
The GCF simplifies fractions and the LCM finds common denominators, making fraction work faster.
When will two buses arrive together? How many identical gift bags can you make? GCF and LCM answer these.
Working with factors and multiples deepens understanding of how numbers are built.
Inside GCF and LCM
A short read-aloud lesson first, then hands-on games and a quiz to lock it in.
Step 1 · Lesson
A short read-aloud lesson in 4 steps, with pictures and worked examples.
Step 2 · Game
Greatest common factor. (6 problems)
Step 3 · Game
Least common multiple. (6 problems)
Step 4 · Game
Use the distributive property. (4 problems)
Step 5 · Game
Decide: GCF or LCM? (4 problems)
Lesson preview
This is the real lesson text your child hears, read aloud by a friendly voice.
The GCF is the biggest number that divides both. Factors of 12: 1, 2, 3, 4, 6, 12. Factors of 18: 1, 2, 3, 6, 9, 18. GCF = 6.
The LCM is the smallest number both divide into. Multiples of 4: 4, 8, 12. Multiples of 6: 6, 12. LCM = 12.
Use the GCF to factor out: 24 + 36 = 12 × (2 + 3).
Use the LCM when things repeat: buses every 4 and 6 minutes meet every 12 minutes.
For parents
Learning sticks best when kids use it in real life. Here are simple ideas from this course.
You have 18 cookies and 24 grapes. Ask your child to find the greatest number of identical snack plates you can make with nothing left over.
Practice
Real questions from GCF and LCM. Try them with your child, then tap to see the answer.
Question 1
5
Question 2
24
Question 3
2
The full course has 20 questions with instant feedback, stars and rewards. Create a free account to play them all.
GCF and LCM · Questions from parents
GCF and LCM is a grade 6 math course for kids ages 11–12. That is Year 7 maths in the UK and Year 6 in Australia. It also works well for review in the next grade, or as a challenge for a confident younger learner.
Find the greatest common factor and least common multiple of two numbers, and use them to solve real problems. Along the way they practice: Find the GCF; Find the LCM; Factor It Out; GCF and LCM Stories.
About 10 minutes in total, split into 4 short levels. Most kids finish it over two or three sessions. Progress is saved, so they can stop any time and pick up where they left off.
GCF and LCM is part of SkillBloom Premium, which unlocks every course in every subject. Each subject also has free courses, so your child can try SkillBloom before you decide.
No. Every lesson has a friendly read-aloud voice, questions are read aloud too, and the pictures help kids follow along. Confident readers can turn the voice off.
Yes. SkillBloom is built for homeschooling families. Kids work through lessons, games and quizzes on their own, and the parent dashboard shows what they finished and which skills need more practice. It works on phones, tablets and laptops.
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