Martha is carrying her biology, science, and math textbooks. Her books weigh a total of 9 pounds. Her biology textbook weighs 3 pounds and her math textbook weighs 40 ounces. How many ounces does her science textbook weigh?
the answer is 56 ounces. 16 ounces equal a pound so the math textbook is 2.5 pounds. add 2.5 and 3 you get 5.5. now leaving you with 3.5 pounds to get to 9. thus the science textbook weighs 56 ounces ( 3.5 pounds )
