First let’s add the whole numbers.
8 + 7 + 6 = 21
Now let’s add the fractions.
1/2 + 1/4 = 3/4 or 0.75
Finally let’s add the whole numbers to the factions.
21 + 3/4 = 21 3/4
Or you can do 0.75
21 + 0.75 = 21.75
So your answer is either 21 3/4 or 21.75
Hope that helps :)