2/5 + 3/12 = 24/60 + 15/60 = 39/60 = 13/20 = 0.65
We convert this to twelfths to give: 10 twelfths + 4 twelfths + 9 twelfths = 23 twelfths or 1 and 11 twelfths.
Four twelfths plus one fourth can be simplified by converting one fourth into twelfths. One fourth is equivalent to three twelfths, so adding four twelfths and three twelfths gives you seven twelfths. Therefore, four twelfths plus one fourth equals seven twelfths.
One fourth is three twelfths. So one twelfth plus three twelfths is four twelfths, which is also one third.
six tenths or three fifths
3 5/8 + 5/12 is 4 1/24.
5
7 4/5
They would have to convert to same denominators to add. So that would be 8 twelfths plus three twelfths. And that is eleven twelfths. 0.916666667
13 and 1 fifth
Seven-twelfths
3/4
five twelfths
We convert this to twelfths to give: 10 twelfths + 4 twelfths + 9 twelfths = 23 twelfths or 1 and 11 twelfths.
The sum is 23/30
twelve and four twelfths
One fourth is three twelfths. So one twelfth plus three twelfths is four twelfths, which is also one third.
six tenths or three fifths