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 operators like addition, subtraction, multiplication or division on the numbers embedded in the text to answer the following question and then only report final the numerical answer.

A physician 's assistant measures a child and finds that his h8 is 41.5 inches . At his last visit to the doctor 's office , the child was 38.5 inches tall . How much did the child grow , in inches ?
3