Multiply 127 x 99 in less than 5 seconds

Suppose we have to multiply a number with another number which consists of all 9s.Another example

In both the above cases, the no. of digits of both the numbers were same. Let's see what happens when the no. of digits of the no. other than the no. of all 9's is less.
Lets see what happens if the no. of all 9's is smaller.