Norman looked at the remaining students with an evil look in his eye. Then they all yelled, “Give us Hannah and David back. Give us David and Hannah back!”

“Never!” yelled Norman.

“You horrible little man, we’re gonna’ tell Mr. R. if you don’t give them back!” yelled Serena.

“Well,” said Norman, “I know Mr. R. loves math problems so maybe I’ll make a little math riddle to see if you’ll get your friends back.”

“What’s the riddle?” yelled Justin.

“This is the riddle, good luck,” laughed Norman as he handed them a sheet of paper with questions on it. It said something a little bit like this:

Solve the following two problems (careful- one’s subtraction and one’s addition) and then find the difference between the two answers. The difference is equal to the number of students I’m going to let you have back before I leave forever!

**The difference between the answers of the two problems is?**

Enter the number here:

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