The GCD of given numbers is 11.
Step 1 :
Divide $ 1111 $ by $ 11 $ and get the remainder
The remainder is zero => GCD is the last divisor $ \color{blue}{ \boxed { 11 }} $.
We can summarize an algorithm into a following table.
1111 | : | 11 | = | 101 | remainder ( 0 ) |
GCD = 11 |
This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.