The most important area of mathematical learning for your child is number. Plenty of first hand counting experience is best and the more counting you do with him the better.
Pass on the message that numbers are fun by demonstrating you enjoy counting too, particularly with him.
Confidence is crucial; take opportunities for counting which occur naturally in play and the routines of his daily life.
No specialist resources are necessary. Games, threading toys, pegboards, small toys, collections from nature and the home make for variety and colour; together with clean supermarket vegetable trays they are all the equipment you need.