The GCD of given numbers is 337.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}337 =& 337\\[8pt]674 =& 2\cdot337\\[8pt]\end{aligned}$$(view steps on how to factor 337 and 674. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}337 =& \color{blue}{\boxed{337}}\\[8pt]674 =& 2\cdot\color{blue}{\boxed{337}}\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 337 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.