Complete factor trees for the numerator and denominator of a fraction to help determine the two numbers' highest common factor (HCF).

For each question students will complete the following process:

1. Complete a factor tree for the numerator and denominator of the fraction.
2. Find pairs of common prime factors.
3. Multiply the common prime factors together to find the HCF.
4. Simplify the fraction by dividing the top and bottom of the fraction by the highest common factor.

The first question’s factor tree has already been completed to help scaffold the activity. An answer sheet is included to help with the breakdown of factors for the two main questions. A blank version of the worksheet is included for students to write their own fractions that they will simplify by finding the highest common factor.

Print one page per student, or if working in small groups, place a few sheets into write-and-wipe sleeves and reuse them for each group of students.