Isaac cut his 30 meters ribbon into 6 equal parts. He then used 4 parts of the ribbon. How many meters of ribbon are not used?
Each part is 30/6 = <<30/6=5>>5 meters long.
Since Liam used 4 parts, then he used 5 x 4 = <<4*5=20>>20 meters of the ribbon.
So, 30 - 20 = <<30-20=10>>10 meters of ribbon is not used.
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