Figure I might as well add here what I just posted elsewhere, which is that Singapore Math is planning to release a digital subscription version of Primary Math grades 1-5 this year. It looks like it is designed for homeschooling parents to do with their children, so not an independent program, nor a computer-adaptive program, but a curriculum-that-is-online. But it should be as flexible as you want it to be, since the parent-teacher controls what and how quickly you do. It includes animated teaching modules, so you don't have to have prior knowledge of the Singapore method to teach it.