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? Let's answer step by step:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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Each part is 30 / 6 = 5 meters long. Since Liam used 4 parts, then he used 5 x 4 = 20 meters of the ribbon. So, 30 - 20 = 10 meters of ribbon is not used. The answer: 10.