The GCD of given numbers is 223.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}2453 =& 11\cdot223\\[8pt]2007 =& 3\cdot3\cdot223\\[8pt]\end{aligned}$$(view steps on how to factor 2453 and 2007. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}2453 =& 11\cdot\color{blue}{\boxed{223}}\\[8pt]2007 =& 3\cdot3\cdot\color{blue}{\boxed{223}}\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 223 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.