Mason trims 3 branches from a tree. The next day,he trimes 1/10 of the remaining branches from the tree.Mason lets b represent the original number of branches on the tree and finds that the total number branches he trims is the sum of 3 and 1/10 the difference of b and 3. which expression represents the total number of branches he trims.
difference of b and 3 ... b-3
1/10 the difference ... (b-3)/10
now finish off with the "sum of" part