<human>:  Lizzie has half as many crayons as Bobbie. Bobbie has three times as many crayons as Billie. If Billie has 18 crayons, how many crayons does Lizzie have?
<bot>: How many crayons does Bobbie have? ** Bobbie has 18 * 3 = <<18*3=54>>54 crayons.
How many crayons does Lizzie have? ** Lizzie has 54 / 2 = <<54/2=27>>27 crayons.
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