This is OP. Thanks so much for your input on this. I wanted to start it for my 6y old. He had good understanding of addition and subtraction. which level should I buy?
How much do we need to spend over an year for the material?
Thanks for your help.

I just give my kid the workbook and have still had good results.

Yes they are fantastic. However, it is a program. The Frank Shaffer Singapore workbooks are not the same as the real textbooks and program. If you want your child to learn how to think about math then you have to buy the home instructor's guide, textbook, and workbook, and manipulatives. You actually need to sit down and teach the program not just put the workbook in front of your child. You can buy the program at singaporemath dot com. If you aren't able to invest the time in teaching the lesson it isn't worth it.

Hello,
I wanted to try singalore math workbooks for my 1st grader.
Anybody using them? Is it helpful? I read over the net about it.
Thanks.