Math for Special Education: Skills for Primary Grades - ThoughtCo Jul 24, 2019 · Counting and Cardinality. One to one correspondence: Students know that sets of numbers correspond to a cardinal number, i.e. the pictures of 3 birds correspond to the number three. Counting to 20: Knowing the number names and order of numbers to 20 builds the foundation for learning place value in the Base Ten System. Understanding whole numbers: …