Binary Numbers

Binary numbers are numbers represented in base 2, which means using only the digits 0 and 1.

Just as in base 10, we have the 1s place, 10s place, 100s place, 1000s place, 10,000s place, etc, in base 2 we have the 2s place, 4s place, 8s place, 16s place, etc.

Below we count up to 32 in base 2:

BASE 2 BASE 10
1 1
10 2

11

 3
100 4
101 5
110 6
111 7
1000 8
1001 9
1010 10
1011 11
1100 12
1101 13
1110 14
1111 15
10000 16
10001 17
10010 18
10011 19
10100 20
10101 21
10110 22
10111 23
11000 24
11001 25
11010 26
11011 27
11100 28
11101 29
11110 30
11111 31
100000 32

Binary numbers are used extensively in computer science.