Per means divide
Per means divide
The word "per" means divide. So average speed is distance per time, and density is mass per volume.
Step-by-step lessons on Eduqas GCSE Maths Speed and Density. Each one builds up to exam-style questions. Build fluency with number, ratio and algebra first, since geometry, probability and statistics topics rely on them, and leave extra time nearer the exam for Higher-tier problem-solving and multi-step reasoning questions.