Step 1 :
Divide $ 437325 $ by $ 7939 $ and get the remainder

$$ 437325 : 7939 = 55 \text{ ( remainder is } \color{blue}{ 680 } \text{ ) } $$

The remainder is positive ($ 680 > 0 $), so we will continue with division.

Step 2 :
Divide $ 7939 $ by $ \color{blue}{ 680 } $ and get the remainder

$$ 7939 : 680 = 11 \text{ ( remainder is } \color{blue}{ 459 } \text{ ) } $$

The remainder is still positive ($ 459 > 0 $), so we will continue with division.

Step 3 :
Divide $ 680 $ by $ \color{blue}{ 459 } $ and get the remainder

$$ 680 : 459 = 1 \text{ ( remainder is } \color{blue}{ 221 } \text{ ) } $$

The remainder is still positive ($ 221 > 0 $), so we will continue with division.

Step 4 :
Divide $ 459 $ by $ \color{blue}{ 221 } $ and get the remainder

$$ 459 : 221 = 2 \text{ ( remainder is } \color{blue}{ 17 } \text{ ) } $$

The remainder is still positive ($ 17 > 0 $), so we will continue with division.

Step 5 :
Divide $ 221 $ by $ \color{blue}{ 17 } $ and get the remainder

$$ 221 : \color{blue}{ \boxed { 17 }} = 13 \text{ ( remainder is } \color{blue}{ 0 } \text{ ) } $$

The remainder is zero => GCD is the last divisor $ \color{blue}{ \boxed { 17 }} $.

This solution can be visualized using a Venn diagram.

The GCD equals the product of the numbers at the intersection.

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