Base 5

The base 5 number system is somewhat difficult to understand. The placement of the numbers goes ones, fives, twenty-five, and so on. They are also known as the powers of five. You write the number out by putting the number of fives that go in that spot, never using any other numbers but 0, 1, 2, 3, and 4. The reason you never use 5 is because once you get to that value, you move it to the next placement. For example, the number 421 base five is really the number 115. This is because the 4 is in the 25's placement, the 2 is in the 5's placement, and the 1 is in the 1's placement. To get 115, you multiply 25 by 4, add that to 5 times 2, and then add that to 1 times 1.

This number system is somewhat confusing to a lot of people at first. It takes a little thinking to learn it and to understand it. Not a lot of places in the world use this method. For a little bit of background or history of the base five number system click here. Like the link tells us, the base five system can also be thought of as the hand based number system. It is used more as a grouping system.