Jon goes to a flea market and sells comic books for 3 dollars each. He starts the night with 20 dollars in his cash register. At the end of the night, he has 47 dollars in his cash register.
How many comic books did Jon sell?

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Which expression is equivalent to sq-80

What number is 7 units left of -15?

The architect's side view drawing of a saltbox-style house shows a post that supports the roof ridge. the support post is 8 ft tall. the distance from the front of the house to the support post is less than the distance from the post to the back of the house. how far from the front of the house is the support post positioned?