Building Blocks

Primes and factorization

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• A prime has exactly two divisors: 1 and itself. 1 is not prime.
• Every number > 1 factors into primes in exactly one way.
• Factorizations make divisors, trailing zeros and more easy to count.

Steps

1. Rectangles of tiles
2. Primes and composites
3. Factorize
4. Count the divisors
5. Only one rectangle
6. Trailing zeros