1-A bit to specify the sign.

2-digits

3-position of the point.

Like this:

0.25 = + 25 *10^-2

-123.456 = - 1233456 *10^-3

25000 = + 25000 *10^0

The first part stores the sign (+ or -). The second store the digits (25 or 123456 or 25000). The third stores the power of ten the number is multiplied by (-2 or -3 or 0)