Lesson · Grade 6 · Mathematics
Greatest Common Factor with a Venn Diagram
- Grade 6
- Mathematics
- 1 min 20 s
- British Columbia
- BC6-MA-10
The video lists the factors of 12 and 18 by finding the pairs that multiply to each number, then sorts them into a Venn diagram: 1, 2, 3 and 6 in the middle, 4 and 12 on the side for 12, and 9 and 18 on the side for 18. It names the middle numbers the common factors, shows that the greatest of them is 6, checks it with 12 ÷ 6 = 2 and 18 ÷ 6 = 3, and ends by saying that the greatest common factor is the largest factor both numbers share.
Concept: Greatest common factor
Anyone can watch two lessons on the website without an account. Signing in is free, no payment and no card, and opens three a day; Plus has no limit.
Loading
In one sentence
The question this lesson answers
What is the greatest common factor of 12 and 18?
Find the pairs that multiply to 12: 1 times 12, 2 times 6 and 3 times 4.
Transcript
What the lesson says
What is the greatest common factor of 12 and 18?
Find the pairs that multiply to 12: 1 times 12, 2 times 6 and 3 times 4.
So the factors of 12, in order, are 1, 2, 3, 4, 6 and 12.
Now find the pairs that multiply to 18: 1 times 18, 2 times 9 and 3 times 6.
So the factors of 18, in order, are 1, 2, 3, 6, 9 and 18.
Now sort these factors into a Venn diagram.
1, 2, 3 and 6 are in both lists, so they go in the middle.
4 and 12 are factors of 12 only.
9 and 18 are factors of 18 only.
The numbers in the middle are called the common factors.
The greatest of these is 6, so 6 is the greatest common factor.
Check: 12 divided by 6 is 2, and 18 divided by 6 is 3.
The greatest common factor is the largest factor that both numbers share.
Curriculum
Where this fits
- British Columbia, Grade 6
Mathematics, Number: factors and multiples: greatest common factor and least common multipleBC6-MA-10
Previous: Prime factorization with a factor treeNext: Least Common Multiple with a Venn Diagram
The outcomes and strands follow the British Columbia curriculum.
Keep going
1 min 26 s15.2 − 7.85
Grade 4 · 1 min 26 s
1 min 37 s2.4 × 1.3
Grade 7 · 1 min 37 s
1 min 4 s3 × 7 = 7 × 3: Equal Groups, Skip Counting and Arrays
Grade 4 · 1 min 4 s
59 s3.75 + 8.6
Grade 4 · 59 s
1 min 32 s7.56 ÷ 0.12
Grade 7 · 1 min 32 s
56 sA Fraction Is Equal Parts of One Whole
Grade 3 · 56 s
57 sA Fraction of a Group
Grade 3 · 57 s
1 min 23 sAdding and subtracting are related
Grade 1 · 1 min 23 s
- All Grade 6 Mathematics lessons
- Teachers: the maths worksheets for Grade 6 are in the dashboard, each with a worked example and a proven answer key.
- Try the graph paper, free for everyone, no account needed.
- Create a free account to watch three lessons a day, no payment and no card.