Math & Numbers Facts for Kids
Mind-bending number facts
Ancient Greek mathematicians could construct many shapes using only a compass and a straight ruler. However, they spent centuries trying to 'square the circle' β construct a square with the same area as a given circle β which was proved impossible in 1882.
The square root of β1 does not exist on the normal number line, so mathematicians invented imaginary numbers to work with it, writing it as 'i'. Despite the name, imaginary numbers are vital for real-world engineering and physics.
The word 'percentage' comes from the Latin 'per centum', meaning 'per hundred'. So 75% simply means 75 out of every 100.
When people are asked to choose a random number between 1 and 10, seven is chosen far more often than any other. Psychologists and mathematicians call this the 'most favourite number' effect.
The area of a circle is calculated using the formula A = ΟrΒ², where r is the radius. If you double the radius of a circle, the area increases by four times, not two.
Twelve is a highly composite number, meaning it has more divisors than any smaller positive integer β it can be divided evenly by 1, 2, 3, 4, 6, and 12. This is why we use 12 in clocks, calendars, and dozens.
Pythagoras' theorem states that in a right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: aΒ² + bΒ² = cΒ². This formula was known in Babylon over a thousand years before Pythagoras.
In many real-life data sets, about 30% of numbers start with the digit 1. This surprising pattern is called Benford's Law and is used to detect financial fraud.
In Britain and America, a decimal point is written as a dot (3.14), but in many European countries a comma is used instead (3,14). This can cause confusion in international science and engineering.
Logarithms were invented by Scottish mathematician John Napier and published in 1614. They allowed complex multiplication to be done by simple addition, making navigation at sea much easier.