The book that ConnectingDots mentioned is written by Susan Assouline.
Also, try AOPS - US schools (or perhaps most schools these days - I am long in the tooth) take an excruciatingly long time to cover basic arithmetic. There is simply not that much covered in 3,4 or 5th grade. Instead of butting your head against the wall only to get a one year acceleration in Maths which may not be enough, try stuff outside of school that will permit them to learn at their own pace...
Last edited by madeinuk; 08/18/15 01:40 PM. Reason: Correction to username spelling
