The golden ratio (symbol is the Greek letter phi shown at left) is a special number approximately equal to 1.618.

Plants can grow new cells in spirals, such as the pattern of seeds in this beautiful sunflower. The spiral happens naturally because each new...

Illustrated definition of Golden Ratio: The number approximately equal to 1.618033989... We get the Golden Ratio when a line is split into two parts so...

The Fibonacci Sequence is the series of numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ... The next number is found by adding up the two numbers before it:

The Pentagram (or Pentangle) looks like a 5-pointed star. You may think it has something to do with witchcraft, but in fact it is more famous as...

Imagine we want to know the exact diagonal of this square tile. No matter how hard we try, we won't get it as a neat fraction!

Illustrated definition of Golden Mean: Another name for Golden Ratio: the number approximately equal to 1.618033989...

A ratio tells us how much of one thing there is compared to another. There are 3 blue squares to 1 yellow square.

Number Skills are very valuable. Counting. Colorable Number Chart. Skip Counting. Number Blocks Freeplay. Place Value.

Illustrated definition of Ratio: A ratio shows the relative sizes of two or more values. Ratios can be shown in different ways: using the...