Greatest Common Divisor

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Find the *Greatest Common Divisor* (GCD) of the numbers 60 and 420.

**Answer**

$60=({2}^{2})(3)(5)$

$420=({2}^{2})(3)(5)(7)$

The GCD of 60 and 420 is the product of the least powers of each prime factor in both.

Thus the GCD of 60 and 420

$=({2}^{2})(3)(5)$

$=60$