Why Are Some Numbers Prime?

Prime numbers are like the building blocks of all other numbers. Think of them as the special Lego bricks that can’t be split into smaller Lego bricks, unless you use just one brick. For example, 2 is a prime number because it only has two friends: 1 and itself. But 4 isn't prime because it can be broken down into 2 × 2, so it's not as special.

Take the quiz →

Examples

  1. A prime number like 3 can only be divided by 1 or 3, making it a special kind of number.
  2. 2 is the smallest prime number, it’s used to count things in pairs, like shoes and socks.
  3. 7 doesn’t fit into any multiplication pattern except 7 × 1 = 7, so it's also prime.

Ask a question

See also

Discussion

Recent activity