WEBVTT

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Here is the problem: Find the greatest common factor of 84, 126.

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Find the greatest common factor (also called GCD or HCF) of the numbers.

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Prime factorization of each number.

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Euclidean algorithm for GCF(84, 126). 126 equals 1 times 84 plus 42; 84 equals 2 times 42 plus 0.

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The last non-zero remainder is the GCF.

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Confirm with shared prime factors. Multiply the primes common to every number, each with its smallest exponent.

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So the answer is 42.

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42 is the largest whole number that divides every number exactly.

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84 divided by 42 equals 2.

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126 divided by 42 equals 3.