The beeb have revision websites and so do s-cool.
Occassionally you may find a site where an answer you are sure of, is not the one on the screen. Sites can be hacked, check with a teacher.
Videos are harder to hack particularly if someone is speaking, and are very informative.
Youtube
Numbee
Hegarty
Specifications are where the topics are shown for the examination.
e.g.
AQA Maths 8300
Topics
Subject content
1 Number
2 Algebra
3 Ratio, proportion and rates of change
4 Geometry and measures
5 Probability
6 Statistics
A Video Link example:-
Raw Maths
https://www.youtube.com/watch?v=RSBt1CrTHa8&feature=youtube_gdata_player
Bridging KS3 to KS4 (GCSE)
http://allaboutmaths.aqa.org.uk/bridgingthegap
CGP Student Books
https://www.cgpbooks.co.uk/Student/books-gcse-maths-new
Amazon links
Sites for students
http://www.mathsgenie.co.uk/grade2.html
NB:-Make a file.
Use a ringbinder divided into two halves
The first half an Alphabetic GCSE list of Mathematics terms
(for cross referencing assessment objectives and alphabetic mathematical terminology that is a list of topics in Alpha order showing each ones definition)
The second half in topic order including your notes, examples, exercises, and video or website links
Useful info
Edexcel
Useful video’s for question papers
https://www.youtube.com/watch?v=oSBke_Yeeuw&feature=youtube_gdata_player
BIDMAS-BODMAS
https://www.youtube.com/watch?v=Z52PiB7UeLE&feature=youtube_gdata_player
UKMathsteacher, link
https://m.youtube.com/channel/UCTzAco9cOFj9gm9ihRxm0iQ
Practice
http://www.mathsisfun.com/worksheets/long-multiplication.php
http://www.mathsisfun.com/worksheets/long-division.php