In a school recycling project, students collect different types of containers to earn credits:
A student collects L L\,L large boxes, M M\,M medium boxes and S S\,S small boxes.
Write an expression for the total number of credits the student earns.
64 exam-style questions on WJEC GCSE Maths Writing an Expression. Each one has a worked solution and a mark scheme showing where the marks go.