The GCD of given numbers is 7.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}203 =& 7\cdot29\\[8pt]833 =& 7\cdot7\cdot17\\[8pt]\end{aligned}$$(view steps on how to factor 203 and 833. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}203 =& \color{blue}{\boxed{7}}\cdot29\\[8pt]833 =& \color{blue}{\boxed{7}}\cdot7\cdot17\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 7 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.