Step 1 :
Divide $ 3200 $ by $ 1120 $ and get the remainder

$$ 3200 : 1120 = 2 \text{ ( remainder is } \color{blue}{ 960 } \text{ ) } $$

The remainder is positive ($ 960 > 0 $), so we will continue with division.

Step 2 :
Divide $ 1120 $ by $ \color{blue}{ 960 } $ and get the remainder

$$ 1120 : 960 = 1 \text{ ( remainder is } \color{blue}{ 160 } \text{ ) } $$

The remainder is still positive ($ 160 > 0 $), so we will continue with division.

Step 3 :
Divide $ 960 $ by $ \color{blue}{ 160 } $ and get the remainder

$$ 960 : \color{blue}{ \boxed { 160 }} = 6 \text{ ( remainder is } \color{blue}{ 0 } \text{ ) } $$

The remainder is zero => GCD is the last divisor $ \color{blue}{ \boxed { 160 }} $.

This solution can be visualized using a Venn diagram.

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

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