Math & Numbers Facts for Kids
Mind-bending number facts
Dividing zero by zero does not give you one or zero β it is undefined, because there is no single answer that makes mathematical sense.
The number 0.999... (with the nines going on forever) is mathematically equal to exactly 1. It is not just 'close to' 1 β it is the same number written in a different way.
If you measure around any circle and divide by the distance across it, you always get the same number: pi, roughly 3.14159.
In the knight's tour puzzle, you must move a knight to every square on a chessboard exactly once. Mathematicians have found solutions using graph theory.
Bees solve a version of the travelling salesman problem every day β they work out the shortest route between flowers, a puzzle that is incredibly hard for computers.
The angles inside any four-sided shape (quadrilateral) always add up to 360 degrees, no matter what the shape looks like.
A 'happy number' is one where, if you keep adding the squares of its digits, you eventually reach 1. For example, 7 is a happy number because 49 β 97 β 130 β 10 β 1.
If you counted one number every second without stopping, it would take about 31.7 years to count to one billion.
Pi is an irrational number, which means its decimal digits go on forever without ever settling into a repeating pattern. No matter how many digits you calculate, the pattern never repeats.
Multiplication is really just a quick way of adding the same number many times. For example, 4 Γ 3 is the same as 4 + 4 + 4.