Math & Numbers Facts for Kids
Mind-bending number facts
Zero is the only number that can't be represented in Roman numerals, and multiplying any number by it always gives zero.
The number 1729 is famous in math because Ramanujan noticed it's the smallest number expressible as the sum of two cubes in two different ways.
The number one is not considered a prime number. A prime must have exactly two distinct factors β itself and one β and the number one only has one factor.
A floating soap bubble is always a sphere because a sphere has the smallest surface area for any given volume β it is nature's most efficient shape.
Every number you will ever see is made up of just ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
The largest known prime number, discovered in 2024, has over 41 million digits. If you tried to write it out by hand, it would stretch for over 100 kilometres.
A googol is 1 followed by 100 zeros. It is more than the number of atoms in the observable universe!
A negative number multiplied by another negative number always gives a positive result. Think of it as reversing a reversal β you end up going forwards again.
The Monty Hall problem shows that if a game show host reveals a losing door, you should always switch your choice β switching gives you a two-thirds chance of winning, even though it feels like 50-50.
If you add up the first n odd numbers, you always get n squared. For example, 1 + 3 + 5 + 7 = 16, which is 4 squared.