He used riddling to talk to Smaug I think because he wanted to stall and waste time as he figured out a plan. He also used riddles to talk to Golem who he clearly was trying to stall to save himself as Golem wanted to kill and eat Bilbo. So it is a reoccurring theme of Bilbo and it makes sense.
<span>starting in medias res if this is the excerpt i think it is
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Greeting's!
<span>d. ms. johnson got books, the pencils and paper from the supply room
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