I use cuisenaire rods. These are the most flexible and fun math manipulatives I have found. I let the children explore with them as blocks. Sometimes without any prompting they start to make the connection that each block represents a number.
I give them numbers they can hold. I ask them to draw the numbers. Any attempt and all results are accepted and encouraged. As they mature, I've seen most young minds correct number direction themselves. How the number looks to me doesn't really matter. They know that their 6 is a 6, no matter which way it goes. They'll turn it around soon enough.
I try to use as many natural examples of numbers as I can. There are seven days in a week. Spiders have eight legs. Rainbows are drawn and created with the number six. There is one sun in the sky. What is a pair? How many pairs can you find on your body? A clock has twelve numbers. A year has twelve months. Your hand has five fingers. The list goes on.
