A quick search brings up the following where someone has asked the same question, but the suggestion is at about A-Level, and in Europe you wont be accepted onto a sponsored course without A-Level maths:
Maths and Physics knowledge req'd for ATPL and airline flying? [Archive] - PPRuNe Forums
It would mainly be the mechanics (rather than pure) parts of the maths course I would expect you to need.
If it helps for comparison, A-Level is the top level qualification for those leaving secondary school (aged around 18) people are likely to get in the UK.
Would you be able to complete the ATPL course with less than that? Yes I'm sure you could but you are more likely to struggle.
At PPL level, the equivalent of GCSE Maths (Mechanics section, taken at aged 16 in the UK) would be ample although through the use of a "Wizz Wheel" even this level wouldn't be required, and it should be within most people's ability.
Judging by your "text speak", you'll need to brush up on your English too!