Sort it out! The sky is the limit when it comes to finding things to sort! Candy, beans, cotton balls, paper clips... you name it! You can even change around how you want it sorted... one time, sort by color, the next time sort by size or shape! My son had a BLAST when I pulled his Matchbox cars to the school table and we sorted them by color! For younger children, you can make it easier by having 'color cards' and have them match the specific objects to the correct card. Older children can just be told to sort out the items by color, shape, etc.
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.
Some of the software is developed in a game format. Children will think that they are playing a game, but in reality are actually learning math. Technology can be great, but I must warn parents to not allow children to spend a lot of unsupervised time on the computer.
They can start with asking simple math questions and going on to harder questions, as the child gets older. Parents should continually ask children mathematical computation questions and give positive feedback when they respond. Children love to receive positive feedback and that encourages continues growth.