20 (number) facts for kids

Twenty is a number that comes right after nineteen and just before twenty-one. It's a number you see and use often in daily life!

Fun Facts About Twenty

Twenty has some interesting math properties. Its prime factors are 2 and 5. This means you can get 20 by multiplying 2 × 2 × 5.

The factors of 20 are 1, 2, 4, 5, 10, and 20. If you add up all its factors (except 20 itself), you get 1 + 2 + 4 + 5 + 10 = 22. Since 22 is more than 20, the number 20 is called an abundant number.

Twenty in Different Cultures

Twenty has been used as a number base in different ways.

• In English, we sometimes say "score" for 20, like "fourscore and seven years ago" (which means 87 years).
• In French, the number 80 is "quatre-vingts," which literally means "four twenties."
• The ancient Mayan people used a base 20 system for their numbers. They likely counted using their fingers and toes!
• In the old English money system, there were twenty shillings in one pound.
• In Japan, people traditionally become adults at the age of 20. This is celebrated on a special day called Seijin no Hi.

Twenty in Shapes and Science

• A polyhedron is a 3D shape with flat faces. A shape with 20 faces is called an icosahedron. It's one of the five special shapes known as Platonic solids. An icosahedron has 20 triangular faces, 30 edges, and 12 corners.
• Did you know that babies usually have 20 milk teeth? These are their first set of teeth before their adult teeth grow in.

Twenty in Roman Numerals

In Roman numerals, the number 20 is written as XX. Each 'X' stands for 10, so 'XX' means 10 + 10 = 20.

See also

In Spanish: Veinte para niños