Here is a fraction: 4/8. What is the simplest way you could write the same amount? Have a think before any hands go up.

Two fraction strips sit one above the other in each example. Watch how the shaded lengths match even though the number of pieces is different. Look for a number that divides into both the top and the bottom.

Let's stack 4/8, 2/4 and ½ on the fraction strips and watch where they all reach the same length. The 2/4 strip is a halfway step between 4/8 and ½. After that we will build 8/12 and 10/12 on the twelfths strip together and decide each one's simplest form as a class.

Let's work through four fractions together. Simplify 6/8, then 9/12, then 24/36, and finally decide whether 7/12 is already in its simplest form. Build each one on the strips and check it against its simplest form.

What we learned today

• A fraction is in its simplest form when the top and bottom share no common factor bigger than 1.
• We simplify by dividing the top and bottom by the same number.
• Finding the greatest common factor gets us there in one step.