For maths, you need to know Year 8 algebra really really well
and even you don't know the Year 9 or 10 ones, year 8 maths will get you there if you know it well enough! (well for me at least anyway)
I remember I don't even know how to do
- Inequalities (3x+2>5)
- Basic Factorising (6x+3=3(2x+1))
Year 9:
- Simultaneous Equations (2x+4=y, 2x+18=22)
- Quadratic Equations (y=ax^2+bx+c) [There's a few variations]
- Factorising Trinomials (x^2+4x+4=(x+2)^2)
- Perfect Squares ((x+2)^2)
- Difference of Perfect Squares ((x+2)(x-2))
Year 10:
- Quadratic Formula
- Completing the Square
You shouldn't be worrying on getting ahead, instead try to make your foundation really strong! It will get you there

Feel free to PM me if you have more questions! I'm more than happy to answer them! (got a superior for maths too!)