Adding a zero on the right of a binary number multiplies it by two, as I mentioned. By shifting a number 1 bit left, each bit has twice the place value it had before, and we bring in a 0 to hold the units place. Multiplication by any power of 2 is possible in this way. For instance, to multiply by 16, shift left 4 bits. Conversely, shifting right divides.
Any remainder is thrown away with the discarded bits.
If the number is positive, we don't want to lose a 1 bit, or have a 1 bit end up in the sign bit, making the result negative. We would like to know if either of these overflow conditions occurred. The actual shift is identical to shift left logical. Programmers typically ignore such flags. Now, you may not quite agree with that answer.