# Binary and denary

- Denary is the same as decimal
- It uses a base 10 number system, in which there are 10 digits, and all other numbers are made up from them

- Binary is discussed here.
- It uses a base 2 number system, in which there are 2 digits, and all other numbers are made up from them

Tables like below are usually used to convert from binary to decimal.

Decimal | 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 |
---|---|---|---|---|---|---|---|---|

Binary |

For example, if you want to know what `00101111`

is in decimal, use the table by adding up the numbers which have a `1`

underneath.

Decimal | 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 |
---|---|---|---|---|---|---|---|---|

Binary | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 1 |

`1 + 2 + 4 + 8 + 32 = 47`