Step 1 :
Divide $ 3551 $ by $ 741 $ and get the remainder

$$ 3551 : 741 = 4 \text{ ( remainder is } \color{blue}{ 587 } \text{ ) } $$

The remainder is positive ($ 587 > 0 $), so we will continue with division.

Step 2 :
Divide $ 741 $ by $ \color{blue}{ 587 } $ and get the remainder

$$ 741 : 587 = 1 \text{ ( remainder is } \color{blue}{ 154 } \text{ ) } $$

The remainder is still positive ($ 154 > 0 $), so we will continue with division.

Step 3 :
Divide $ 587 $ by $ \color{blue}{ 154 } $ and get the remainder

$$ 587 : 154 = 3 \text{ ( remainder is } \color{blue}{ 125 } \text{ ) } $$

The remainder is still positive ($ 125 > 0 $), so we will continue with division.

Step 4 :
Divide $ 154 $ by $ \color{blue}{ 125 } $ and get the remainder

$$ 154 : 125 = 1 \text{ ( remainder is } \color{blue}{ 29 } \text{ ) } $$

The remainder is still positive ($ 29 > 0 $), so we will continue with division.

Step 5 :
Divide $ 125 $ by $ \color{blue}{ 29 } $ and get the remainder

$$ 125 : 29 = 4 \text{ ( remainder is } \color{blue}{ 9 } \text{ ) } $$

The remainder is still positive ($ 9 > 0 $), so we will continue with division.

Step 6 :
Divide $ 29 $ by $ \color{blue}{ 9 } $ and get the remainder

$$ 29 : 9 = 3 \text{ ( remainder is } \color{blue}{ 2 } \text{ ) } $$

The remainder is still positive ($ 2 > 0 $), so we will continue with division.

Step 7 :
Divide $ 9 $ by $ \color{blue}{ 2 } $ and get the remainder

$$ 9 : 2 = 4 \text{ ( remainder is } \color{blue}{ 1 } \text{ ) } $$

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

Step 8 :
Divide $ 2 $ by $ \color{blue}{ 1 } $ and get the remainder

$$ 2 : \color{blue}{ \boxed { 1 }} = 2 \text{ ( remainder is } \color{blue}{ 0 } \text{ ) } $$

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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