(Click on a product to view it in the
Amazon store.)
For your information, the resources I typically provide
as part of my service are detailed below.
Scientific Calculator:
I particularly recommend the calculator below as it displays mathematical expressions (especially fractions) "naturally" as if they were handwritten.

Textbooks:
Make the best use of tuition by trying exercises before sessions to highlight weaknesses. Textbooks have plenty of exercises, whereas revision guides tend to contain relatively few. The best way to revise is to test yourself regularly.
The Oxford series of textbooks below are quite compact. I generally recommend a book to students initially, and then move up the series to the higher books when students are ready.
The "Foundation PLUS" Textbook is targeted at those aiming for Grades C - E:
The "Higher" Textbook is targeted at those aiming for Grades B - D:

The "Higher PLUS" Textbook is targeted at those aiming for Grades A* - B:

I also frequently use Pearson books (not shown) for those studying towards an AQA GCSE Maths qualification.
As well as textbooks, there are packages of past examination papers available, which students may find useful in preparing for their final GCSE exams.
Edexcel Foundation:

Edexcel Higher:
