The GCD of given numbers is 1111.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}1111 =& 11\cdot101\\[8pt]1111 =& 11\cdot101\\[8pt]\end{aligned}$$(view steps on how to factor 1111 and 1111. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}1111 =& \color{blue}{\boxed{11}}\cdot\color{red}{\boxed{101}}\\[8pt]1111 =& \color{blue}{\boxed{11}}\cdot\color{red}{\boxed{101}}\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 11\cdot101 = 1111 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.