Mastery fractions - finding the perimeter of shapes with lengths that include fractions.

I have attempted to write a mastery lesson for my year 8 set 3 (of 4) class. There is a fairly challenging starter which ass the students to add two fractions, before moving on to adding 4 fractions and then mixed number fractions.

Then there is an introduction to finding the perimeter of a rectangle and then finding a length when given the width and the perimeter. The answers to these questions are not all integer values.

Then there are questions on finding the perimeter when the lengths are given as fractions.

This is repeated for finding the perimeter or missing lengths for triangles

There are slides that ask students to discuss ideas, and brings in other ideas such as equilateral triangles and estimating.

The plenary asks students to make up their own lengths for the shapes that have to meet the given criteria.