Grade 6, Operations
Greatest common factor
Find the greatest common factor of two numbers by listing their factors.
Three levels
One skill, rising difficulty
Each sheet carries one level. The three are the same skill at rising difficulty, each named for what it practises.
- Level 1: Numbers to 30
- Find the greatest common factor (GCF). List the factors of each number to help.
- Level 2: Numbers to 60
- Find the greatest common factor (GCF). List the factors of each number to help.
- Level 3: Numbers to 100
- Find the greatest common factor (GCF). List the factor pairs of each number to help.
Worked example
How the sheet explains it
The helper printed at the top of each sheet: one solved example and the steps a student follows, before the first question. Every number sentence in it is proven by the same checker as the answer key.
Level 1: Numbers to 30
GCF of 12 and 18 = 6
- Factors of 12: 1, 2, 3, 4, 6, 12.
- Factors of 18: 1, 2, 3, 6, 9, 18.
- In both lists: 1, 2, 3 and 6. The greatest is 6.
Level 2: Numbers to 60
GCF of 42 and 56 = 14
- Factors of 42: 1, 2, 3, 6, 7, 14, 21, 42.
- Factors of 56: 1, 2, 4, 7, 8, 14, 28, 56.
- In both lists: 1, 2, 7 and 14. The greatest is 14.
Level 3: Numbers to 100
GCF of 72 and 90 = 18
- Factor pairs of 72: 1 × 72, 2 × 36, 3 × 24, 4 × 18, 6 × 12, 8 × 9.
- Factor pairs of 90: 1 × 90, 2 × 45, 3 × 30, 5 × 18, 6 × 15, 9 × 10.
- Factors in both: 1, 2, 3, 6, 9 and 18. The greatest is 18.
Goes with
Reference sheets
One-page helpers a student keeps beside this sheet:
- Factors and multiples
- Divisibility rules
- Prime numbers
Every reference, facts and support sheet is listed in the worksheet catalogue.
In the BC curriculum
Content standards
The British Columbia content standard this skill is written for, by the codes used across this site:
- bc.math.6.c.4
The wording of each standard is on the Province's mathematics curriculum page.
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