The GCD of given numbers is 45.
Step 1 :
Divide $ 1890 $ by $ 45 $ and get the remainder
The remainder is zero => GCD is the last divisor $ \color{blue}{ \boxed { 45 }} $.
We can summarize an algorithm into a following table.
1890 | : | 45 | = | 42 | remainder ( 0 ) |
GCD = 45 |
This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.