Singapore Math is a curriculum developed by the education ministry of Singapore, but that has become popular with homeschoolers and many private schools in the US. Singapore math books are said to be responsible for the high rankings of Singapore students in the math TIMSS tests.
You can order from these 2 suppliers of SM in Singapore: (Comment: Popular is cheaper, but you need to read descriptions on the Times one. – Julia) Find it at Popular Bookstore or Times Bookstore or out of the US with US versions of the textbooks (non-metric) at higher prices from the Singapore Math site.
You can also watch Singapore math concepts and teaching principles at work …follow this link and the others to demonstrations on Singapore math: Youtube Sandy Chen Singapore Math in the Classroom ;
Singapore Math in action;
Singapore Math: Grade 3a, Unit 1 (part 1)