Your academic record may not reflect your actual ability, however, this record will affect your opportunities.  You may be able to raise your standardized scores by studying and practicing before you take the SAT/ACT/ASVAB or other employment tests.  Standardized math tests include basic arithmetic and algebra concepts that you may have never learned, or have forgotten.  If you have a low math score a little studying and practicing can raise it. 

ACT AcademyFree practice for the ACT
Practice TestsFree Accuplacer practice tests.
ASVAB PracticeOfficial ASVAB practice test
Free ASVAB practiceFree ASVAB practice test
Kaplan ACT PrepFree Kaplan ACT Prep
SAT Prep Khan AcademyFree SAT Prep
What is covered on ACTMath topics covered on ACT for each score range
Khan AcademyMath Practice
Math PracticePretty good math practice
High level STEMHigher level STEM instruction
Open Courses MITFree online courses from MIT
Classic Learning TestSome colleges are using CLT instead of ACT or SAT for entrance exams.