I think I have become a bit of a Math curricula expert at this point. Things I have tried:
Math-U-See
Saxon
Singapore
EPGY
Kumon
Life of Fred
Mathmaster.org
Schoolhouse rock (multiplication songs)
They all seem to have their high and low points. I for a time I used both Math-U-See together with Singapore and found that this made things somewhat complete : )The two things that I use and still really like about Math-U-See - especially for kids of that age are the manipulatives and the CD song book (I would note that about half of the CD songs have quite a religious tone - but I was OK with that, and you can skip to the non-religious side of the CD if you want). My daughter learned all of her skip counting songs early and I think that helped things quite a bit when it came time for multiplication. I found that I needed manipulatives with Singapore to break down more difficult concepts, but that just might be my kid. The thing that is great about any of these curricula is that you can choose exactly what you think you need and leave the rest. Saxon does a really great job with the non-calculation based stuff (time and money, shapes, graphs etc but it is a fortune - I was able to pick mine up for a steal at a used curriculum fair).... if you ever need any extra practice of any concept - mathmaster.org is free and most amazing. Schoolhouse rock songs can be found for free on the Pandora "Schoolhouse rock" station - nothing like "figure 8...is double 4, figure 4 is half of 8...." ...love that one. Good luck!