Binary Numbers.

Binary is the simplest numbering system, as digits are limited to only two possible symbols, (0 & 1).

A binary digit is given a special name, it is called a bit.
Quantities greater than one, are written using two or more bits.

1.
10.
100.

Like decimal the bits have different weightings, but in binary the weightings increase by a factor of 2, moving from right to left.

The symbol 1, in each of the above example represents:

One in example i).
Two in example ii).
Four in example iii).

e.g.

in example i) the right hand digit value is, 1 x 2⁰ = 1 x 1 = 1.
in example ii) the middle digit value is, 1 x 2¹ = 1 x 2 = 2.
in example iii) the left hand digit value is, 1 x 2² = 1 x 4 = 4.

The left hand bit in a binary number has the greatest weighting and is called the most significant bit (m.s.b.). The right hand bit in a binary number has the lowest weighting and is called the least significant bit (l.s.b.).