Answer :
First you line up the decimal point then you add 20.30 + 7.6
Second you get the answer which is 27.90
To subtract you would have to add a 0 to 7.60 and subtract 20.30-7.60=12.7
First you line up the decimal point then you add 20.30 + 7.6
Second you get the answer which is 27.90