there are 9 books eack book 3/4 of a pound which is the total weight of the books?

Total Weight = Weight of the book + Weight of the CD + Weight of the box  Total Weight = 1 1/4 pound + 1/5 pound + 3/10 pound  Total Weight = 5/4 + 1/5 + 3/10  To add these fractions, you need to put them over a common denominator.  To do that, find the least common multiple of 4, 5, and 10.  Below is a table of the multiples.  The least multiple they have in common is 20, shown in orange.  So use 20 as your least common denominator.             1      2      3      4     5      6     7 4 x      4     8     12    16   20    24   ... 5 x      5    10    15    20   25    30   ... 10 x   10   20   30    40    50    60   ...  Can you finish it from here?