60 Seconds and 1 minute aren't really the same? This is a bit of a random question, but the answer sbeen bugging me for a long time. so... a microwave, if you push 60, then it will cook for 60 seconds

60 Seconds and 1 minute aren't really the same?
This is a bit of a random question, but the answer sbeen bugging me for a long
time. so...
a microwave, if you push 60, then it will cook for 60 seconds or one minute.
(Following
AND if you also press 1:00 it will cook for one minute, or 60 seconds. (Right, right?)
my question is....
you add 1:00 1:00 it is 2:00 right? So your food will cook for a total of two
minutes.
BUT if you add 60 seconds 60 seconds it will only cook for one minute and twenty
seconds. Even though 60 seconds is one minute?
{i know, confusing question.)
guess to put it into simpliest terms, How corne 1 minute 1 minute 2 minutes, but
60 seconds 60 seconds only one minute and twenty seconds?