Electricity can be on or off. That's it. So how do computers hold numbers?

A bicycle has two wheels, a binomial has two... nomials, and we (humans) are bipedal - we have two feet! Electricity *has two states* - on (1) and off (0). This means we need a number system that allows us to count using only two digits.

Decimal vs. Binary

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Our decimal number system has ten 'digits', just like our fingers - which we also call digits (similar to 'digital' - no?). Our placeholders can have any of the digits 0 1 2 3 4 5 6 7 8 9. Once over 9, we increase the next placeholder by one and roll the 9 to 0.

Since electricity can either be **on (|)** or **off (O)**, ether **flowing (1)** or **not flowing (0)**, we are unable to use the decimal system to represent numbers - **we only have two states, not ten!**

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**Other great videos:
** - Binary Numbers and Base Systems | As Fast as Possible
- Binary Tutorial - written samples