GMAT tests a limited set of concepts and therefore with proper plan and hardword you can do good in this test. Pick any standard gmat book (Kaplan
/PR) and go through basics. Also go through basics in the beginning of OG for concepts.
Come back and practice as many questions as you can here in math forum
. Also, there are tons of information for all levels in the stickys.
Active participation and shared learning should help. It did to me.
Whether you think you can or think you can't. You're right! - Henry Ford (1863 - 1947)