Your child now has a vast knowledge and skill base to handle his simple math problems. He can easily manage addition and subtraction and will be moving to multiplication and division now. Your child also has an understanding of place values and can count up to 4 digits. The ability to count numbers up to 4 digits is because now he is able to do mental additions. His active memory is also working sharply and his mind is already working on the next number even while he is counting the numbers.
What you need to know
Mathematically, most kids this age have a strong number sense as well as estimation skills. However, do remember that every child is unique and has their own pace. Do not compare your child to anyone else and then expect him to perform accordingly. Maths can never be forced, however practice and encouragement will help your child learn all the math skills better and faster.