Greatest Common Factor Worksheet

This greatest common factor worksheet gives fifth grade students structured practice with the skill that sits underneath simplifying fractions, splitting quantities into equal groups, and every later lesson on prime factorization. Students list every factor of two numbers, circle the factors the pair shares, and then name the largest one. Working the whole factor list by hand is the point: a student who only memorizes a shortcut cannot explain why twelve is the greatest common factor of twenty-four and thirty-six, while a student who has written both lists can see it. Four paired-number items build that habit before the sheet asks for it in context.

The page finishes with two word problems that put the skill to work. One asks how many identical art kits a teacher can pack from twenty-four markers and thirty-six crayons; the other asks for the longest equal piece a crafter can cut from thirty-six inches of red ribbon and forty-eight inches of blue. Neither problem announces which operation to use, so students have to recognize the greatest common factor as the tool that fits. Each problem sits in its own card with a generous work space above the answer line, so there is room to list factors, try a guess, and cross it out. A full answer key is included on the second page, with every shared factor circled exactly the way students are asked to circle it.

What’s Included

• 1 print-ready PDF worksheet, 2 pages
• 4 paired-number items with factor lines and a GCF line
• 2 real-world word problems with work space and an answer line
• A complete answer key with the shared factors circled
• A Name and Date row for classroom use

Three Reasons This Helps Kids

• It makes the reasoning visible. Writing both factor lists shows students where the shared factors come from instead of asking them to trust a rule.
• It builds a habit of checking. Circling every shared factor before choosing the largest one catches the common mistake of stopping at the first match.
• It transfers. The same list-and-compare move reappears in simplifying fractions and in finding a least common multiple.

Teacher and Parent Ideas

Work item one together on a whiteboard before students start, saying each factor pair out loud as you write it. Ask a student to explain why a number can never have a factor larger than itself, which prevents the most common listing error. For a quick review the next day, call out a pair of numbers and have students list factors on scrap paper against a timer. This greatest common factor worksheet also pairs naturally with a least common multiple page, since the two skills use the same lists from opposite ends. Homeschool families can keep the answer key beside them and check the four factor items together before the word problems. This 5th grade factors worksheet works equally well as guided practice, as homework, or as a quick check before a unit test on fractions.

Related Resources

• Just the Factors Worksheet
• Least Common Multiple Worksheet
• 2 Digit Multiplication Worksheet
• Prime Numbers Song