Start with regular counting from 1 to 10 with your child to make sure they've mastered it, then explain the idea of «jumping» by two: instead of saying 1, 2, 3, 4, we'll say just 2, 4, 6, 8, 10.
Use physical objects to make it concrete: place 10 small items (buttons or blocks) on the table, ask your child to group them into pairs of two, then count the pairs together: one pair (2), two pairs (4), three pairs (6)... and so on.
Repeat the activity daily for a few minutes until your child memorizes the sequence. This exercise builds early number-sense around patterns, and later makes it easier to understand addition and multiplication in school.
