Numbers and math
A number line is infinite in both directions. Numbers are a convenient way for people to organize their thoughts about space and time. First we can think of zero as a point, taking up no [...]
A number line is infinite in both directions. Numbers are a convenient way for people to organize their thoughts about space and time. First we can think of zero as a point, taking up no [...]
A fraction of a pie: What are fractions? We started with whole numbers When we first thought about the number line, we counted only in whole numbers - we went straight from zero [...]
What are factors? Factors of a number: Three is a factor of nine. What are factors of a number? A factor is a whole number that fits evenly into another whole number. [...]
This is a square. The darker purple line is the perimeter of the square. Using exponents is a short way of saying "multiply the number by itself." The little number [...]
A pie cut into thirds The denominator of a fraction is the number on the bottom (the top is the numerator). In the fraction 1/2, the denominator is 2. In the fraction 45/66, the denominator [...]
A number line is infinite in both directions. Decimals, like fractions, are a way of describing points on the number line that fall in between the whole numbers. If you were using fractions, you'd [...]
A fraction of a pie If you want to add two fractions together, both fractions must have the same denominator. That's okay if you want to add 1/9 and 4/9 = 5/9. But what if [...]
An infinite distance: stars in the sky Why do we use exponents? Some numbers are so big that it's hard to write them in the regular way. The number line [...]
History of Math: Counting tokens from Mehrgarh in Late Stone Age India Indian counting tokens and base 10 The first Indian numbers appeared in the late Stone Age, about 4000 BC. Around this time, [...]
How the alphabet evolved People in ancient Greece had a variety of different ways of writing down numbers, but none of them was very efficient. (And of course different Greek city-states used somewhat [...]