I've found that using Maths based games is always a great starting point. Making learning fun can make it seem as if you aren't learning at all. Then when you child is a bit older (around 3-4),
 i've found using sites like https://www.khanacademy.org/ and https://tutora.co.uk/search/maths can be great ways to explore new ways of learning, to find which way suits your child best.