This is Part 4 of a four part series covering valuable material for your GCSE Key Stage 4 mathematics and is also part of theCambridge Maths Method. If you have not already worked through Parts 1, 2, and 3, you are recommended to do so. Themajority of the chapters in this book require the use of the Casio fx-991ES Plus which contains some very powerful features.Learning to use this calculator will enhance your maths skill set and lead you to success.