question: Marty has 100 centimeters of ribbon that he must cut into 4 equal parts. Each of the cut parts must be divided into 5 equal parts. How long will each final cut be?
answer: The 100-centimeter ribbon is cut into 4 equal parts in pieces of 100 / 4 = <<100/4=25>>25 cm
  From each piece of 25 cm, he gets 5 equal parts of 25 / 5 = <<25/5=5>>5 cm each.
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