Two digits. Countless uses.
Binary uses just two digits: 0 and 1.
One printable page with the original image and complete lesson.
Question
How can a computer work with information using only zeros and ones?
Answer
Binary is a number system with two digits: 0 and 1. A bit is a binary digit. Combinations of bits can represent numbers and, through agreed-upon codes, text, pictures, and sounds.
History
In 1703, Gottfried Wilhelm Leibniz wrote an explanation of binary arithmetic. The mathematics came long before the electronic computers that would put it to widespread use.
Example
Our familiar place values grow by tens: 1, 10, 100. Binary place values grow by twos: 1, 2, 4, 8. In the binary number 1011, the 1s select 8, 2, and 1. Add them to get eleven.
Insight
A zero still matters. It holds a place and tells us that its value is not included. In 1011, the zero means we do not add the 4.
Connection
Understanding bits helps us see that digital technology follows rules we can investigate. The tools may be complex, but their foundations can be learned one step at a time.
Challenge
Label four cards 8, 4, 2, and 1 from left to right. Use a 1 for each selected value and a 0 for each unused value. Make eleven, then six and nine. Check after trying: six = 0110; nine = 1001. Explain one zero.