Move to the number

Pick a number (One that your child is trying to grasp the concept of how many that number is) and then pick a way to move your body (i.e. jump, march, smile, etc).  Then do that movement that number of times.

For example:
  ~Stomp 3 times
  ~Smile 3 times
  ~Clap 3 times

When you want your child to review mulitiple numbers, then do the movements different number of times.

For example:
  ~Stomp 3 times
  ~Smile 7 times
  ~Clap 2 times
  ~Clap 6 times

Practice Writing the Number

Which ever number your child is learning about, he can practice writing it.  Get some paper and pencils.  Then, you write the number first.  Let your child trace it with his pencil, or write next to yours.  Practice a few times and when the child is ready, see if he can do it without your help.

Practice Counting

Get a whole bunch of one item, like paper clips.  Count each paper clip with your child.  (You can predetermine how many paper clips there will be, so that your child can practice counting as far as you would like him to learn).

Once you have counted all those items, pick another item and count some more!