Joanna is carrying her books to school in her backpack. Her library book weighs \dfrac{3}{8} 8 3 ​ start fraction, 3, divided by, 8, end fraction of a kilogram, her science book weighs \dfrac{11}{8} 8 11 ​ start fraction, 11, divided by, 8, end fraction kilograms, and her math book weighs \dfrac{5}{8} 8 5 ​ start fraction, 5, divided by, 8, end fraction kilograms.