Step 1 : Find prime factorization of each number.

$$\begin{aligned}2030 =& 2\cdot5\cdot7\cdot29\\[8pt]756 =& 2\cdot2\cdot3\cdot3\cdot3\cdot7\\[8pt]\end{aligned}$$

(view steps on how to factor 2030 and 756. )

Step 2 : Put a box around factors that are common for all numbers:

$$\begin{aligned}2030 =& \color{blue}{\boxed{2}}\cdot5\cdot\color{red}{\boxed{7}}\cdot29\\[8pt]756 =& \color{blue}{\boxed{2}}\cdot2\cdot3\cdot3\cdot3\cdot\color{red}{\boxed{7}}\\[8pt]\end{aligned}$$

Step 3 : Multiply the boxed numbers together:

$$ GCD = 2\cdot7 = 14 $$

This solution can be visualized using a Venn diagram.

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

GCD Calculator