🎓 Deeper Dive — Adults

Counting feels trivial — but it is the foundation of arithmetic, set theory, and combinatorics.

The natural numbers ℕ = {0, 1, 2, 3, …} are used in every counting problem. Cardinality measures how many elements a set has.

Skip counting prepares you for multiplication (5×3 = count by 5 three times). Reverse counting prepares you for subtraction.