If your low score in General Certificate of Secondary Education (GCSE) math is preventing you from attending college or university, there are several options for a retake to try and improve your score. You don't necessarily have to retake the entire exam: if you are a student who is still in senior school (high school), you may be eligible to just retake a single unit instead of the entire exam. Students who have already left senior school have a couple of different options to retaking the entire exam: studying at a sixth form college or studying from home.
Speak to your math teacher about retaking the exam, or sections of the exam. Some exam boards in the United Kingdom charge fees for retakes, and some do not. Your subject teacher and examinations officer will know the fees for your locale.
Seek out a sixth form college offering a GCSE retake class if it's not possible for you to take your exam at your original school. These retake courses can help you brush up on the areas you had difficulty with. For example, the average student in a math retake class at Brighton, Hove & Sussex Sixth Form College (BHASVIC) improved his GCSE score by two letter grades.
Study at home if you feel that you don't need further instruction. Call your local schools and colleges to find out if they will accept outside candidates for GSCE exams.
Plan ahead for your retake. GCSE mathematic retakes are held once a year, in November.