Step 1 :
Divide $ 5981 $ by $ 731 $ and get the remainder

$$ 5981 : 731 = 8 \text{ ( remainder is } \color{blue}{ 133 } \text{ ) } $$

The remainder is positive ($ 133 > 0 $), so we will continue with division.

Step 2 :
Divide $ 731 $ by $ \color{blue}{ 133 } $ and get the remainder

$$ 731 : 133 = 5 \text{ ( remainder is } \color{blue}{ 66 } \text{ ) } $$

The remainder is still positive ($ 66 > 0 $), so we will continue with division.

Step 3 :
Divide $ 133 $ by $ \color{blue}{ 66 } $ and get the remainder

$$ 133 : 66 = 2 \text{ ( remainder is } \color{blue}{ 1 } \text{ ) } $$

The remainder is still positive ($ 1 > 0 $), so we will continue with division.

Step 4 :
Divide $ 66 $ by $ \color{blue}{ 1 } $ and get the remainder

$$ 66 : \color{blue}{ \boxed { 1 }} = 66 \text{ ( remainder is } \color{blue}{ 0 } \text{ ) } $$

The remainder is zero => GCD is the last divisor $ \color{blue}{ \boxed { 1 }} $.

This solution can be visualized using a Venn diagram.

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

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