This teacher should believe in giving homework every night. Homework reinforces what was taught and learned in class and gives the parent and the teacher a chance to see if the child understands that information.
Computer based math practice problems are helpful in training children how to use math skills in real life while still using tried and true methods of testing. As with the old-school techniques, modern math programs also use multiple choice, fill in the blank and true or false questions to quiz students.
Get in the Kitchen! I was very hesitant for a while with my son when it came to the kitchen. I worried about the GIANT mess that would be left when he was done "helping". You don't even have to take on the entire project with them! You can start small and let your child help with measuring certain ingredients. You can modify the difficulty of the 'lesson' by talking about the different kinds of measuring cups and seeing what other measurements can also add up to equal one cup, etc.
Elementary teachers and parents play the biggest role in a child's mathematical development, especially from Kindergarten through Fourth Grade. Time spent in school learning math or not learning math can never be replaced. Parents should make sure the elementary math teacher is knowledgeable and is a good teacher.