question: Patrick has three glue sticks that are partially used. One has 1/6 left, the second has 2/3 left and the third one has 1/2 left. If a glue stick is 12 millimeters long originally, what is the total length of the glue sticks that are not used?
answer: The first glue stick has 12 x 1/6 = <<12*1/6=2>>2 millimeters left.
  The second glue stick has 12 x 2/3 = <<12*2/3=8>>8 millimeters left.
  The third glue stick has 12 x 1/2 = <<12*1/2=6>>6 millimeters left.
  There are a total of 2 + 8 + 6 = <<2+8+6=16>>16 millimeters of glue sticks that are not used.
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