Given a math word problem, answer the following question. You might need to apply addition or subtraction mathematical operators on the numbers embedded in the text to answer the question and then only report the final numerical answer.
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Question: a store has 49 shirts . after selling some there were 28 left . how many did they sell ?

Answer: 21

Question: the tallest giraffe at the zoo is 96 inches tall . there are 14 adult giraffes at the zoo . the shortest giraffe is 68 inches . how much taller is the bigger giraffe ?

Answer: 28

Question: morgan has 65 red pens 45 blue pens and 58 black pens . how many pens does she have ?

Answer:
168