I'm using Teaching Textbooks for math with my son and I LOVE IT! Seriously, it is the best homeschooling math program EVER! You can click on the grade level you're interested in (they're coming out with 3rd grade next month, which I'll get for my daughter
We use Saxon Math. I used to use Math U See and if your kid is in Public school you will not want to use this. It's a great program but they go through addition one year then subtraction one year and so on. One of the complaints about this program has been the testing skills for early elementary. By the time they hit the older ages they are caught up but if you are wanting to supplement you have to decide what exactly what are your goals. Is it for paralleling your school program or is it math fact practice?