My 9 year old is halfway through Epsilon, and that’s after doing Teaching Textbooks for a while, then deciding he wanted to go back to MUS. I let him go as fast as he wants as long as he’s doing well retaining things. One thing we do is have Friday as either a day off math if he’s worked hard all week, or he can do math games on http://www.arcademicskillbuilders.com or multiplication.com. The problems he misses are almost always because of a regrouping or multiplication error that he sees as soon as he does the problem again. He goes too fast, and tries to do too much in his head, so every now and then I print worksheets from MUS on basic multiplication/division/subtraction, etc. He would possibly like to do engineering as well, so like another poster said it would be good to get through higher math and have extra time to go slowly through it if needed.
LindseyD: I don’t think there is a “behind/ahead” in math (although I’m sure state standards disagree) because I think each kiddo is so different. My 5 year old son loves and gets math, and is already doing well with multiplication but his 6 yr old sister is struggling through Alpha, and his other sister is slowly plodding through Gamma. I try to not make a big deal of what book they are in with MUS and I really like that they don’t have a grade level on the book anywhere like other curriculum does so they don’t feel behind because of that.
We are also hoping/encouraging them to opt out of college/be more creative to earn a degree, but I think if your child is skilled in specific areas it doesn’t hurt to move quickly and encourage those skills.