I took Database System Class and Courses in University, and told to store the password using its hash and don't store it in plain text; it is at least a standard.

today i just resetting my gmail password since i forgot the password. and i wonder by how google forgot password mechanism work.

for example i register the password with:
'xxxfalconxxx'
and then change it to:
'youarebaboon123'

sometimes later i forgot both password, and google asked for the last password i remember; and i only remember part of it so i entered:
'falcon'

and this is right, so i can continue the forgot password mechanism. how could you check the hashed text of 'falcon' is the subset of hash text 'xxxfalconxxx' ?