ExplanationPick one of the numbers and list all of its factors. The factors of 120 are: 1 & 120, 2 & 60, 3 & 40, 4 & 30, 5 & 24, 6 & 20, 8 & 15, 10 & 12. Since the problem specifically asks for factors “greater than 1,” eliminate 1 now. Now cross off any factors that do not go into 210:
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Now cross off any factors remaining that do not go into 270. Interestingly, all of the remaining factors (2, 3, 5, 6, 10, 15, 30) do go into 270. There are 7 shared factors.
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