✖️ 6th grade math · Multiply & Divide

Greatest factor, least multiple

A factor divides a number with nothing left. A common factor divides two numbers. Factors of 36 and 48 that match: 1, 2, 3, 4, 6, 12. The greatest is 12.

Worked example

What is the greatest common factor (GCF) of 20 and 25?

Answer: 5

Factors of 20: 1, 2, 4, 5, 10, 20. Factors of 25: 1, 5, 25. The biggest factor in every list is 5.

For grown-ups: GCF and LCM. Below: three problems to try with the worked answers, and a free printable sheet. Children can practise the same skill as a game, with no sign-up and no ads.

CCSS 6.NS.B.4

What this practises, for teachers

Practices gCF and LCM (6.NS.B.4). A printable sheet with its answer key, worked answers on the page, no accounts.

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For your class

🖨️ Printable sheet and key

On the board with this skill:

More printables, with answer keys, for this grade:

Long division worksheets: three-digit by two-digit

Try three

What is the greatest common factor (GCF) of 12 and 10?
Show the answer and how
Answer: 2
Factors of 12: 1, 2, 3, 4, 6, 12. Factors of 10: 1, 2, 5, 10. The biggest factor in every list is 2.
A coach splits 60 players in red and 90 players in blue into identical teams with no one left out. What is the most teams?
Show the answer and how
Answer: 30
Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60. Factors of 90: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90. The biggest factor in every list is 30. That is teams.
What is the greatest common factor (GCF) of 12 and 54?
Show the answer and how
Answer: 6
Factors of 12: 1, 2, 3, 4, 6, 12. Factors of 54: 1, 2, 3, 6, 9, 18, 27, 54. The biggest factor in every list is 6.

Before and after

Learn first: Long division (6th)

Name: ____________________Date: ____________Score: ____ / 12

Greatest factor, least multiple (6th grade)

What is the greatest common factor (GCF) of 24 and 18?
What is the greatest common factor (GCF) of 9 and 15?
What is the greatest common factor (GCF) of 9 and 12?
What is the greatest common factor (GCF) of 12 and 8?
What is the greatest common factor (GCF) of 80 and 50?
A florist has 40 roses and 32 tulips. She makes identical bouquets with no flowers left over. What is the greatest number of bouquets?
A teacher has 6 pencils and 9 erasers to put in identical kits with none left over. What is the most kits that can be made?
What is the greatest common factor (GCF) of 136 and 102?
A baker has 112 muffins and 84 cookies to pack in identical boxes with nothing left over. What is the most boxes?
What is the greatest common factor (GCF) of 108 and 72?
What is the greatest common factor (GCF) of 126 and 90?
What is the greatest common factor (GCF) of 63 and 14?

Try three

Before and after

Greatest factor, least multiple (6th grade)

Answer key