Given the task definition and input, reply with output. You are given a math word problem and you are supposed to apply a single mathematical operator like addition, subtraction, multiplication, or division on the numbers embedded in the text to answer the following question and then only report the final numerical answer.

ted and fred measured their height . fred 's height is 98 inches . ted is 39 inches tall . what 's the difference between ted 's height and fred 's height ?

59