The GCD of given numbers is 5.
Step 1 : Find prime factorization of each number.
$$\begin{aligned}890 =& 2\cdot5\cdot89\\[8pt]525 =& 3\cdot5\cdot5\cdot7\\[8pt]\end{aligned}$$(view steps on how to factor 890 and 525. )
Step 2 : Put a box around factors that are common for all numbers:
$$\begin{aligned}890 =& 2\cdot\color{blue}{\boxed{5}}\cdot89\\[8pt]525 =& 3\cdot\color{blue}{\boxed{5}}\cdot5\cdot7\\[8pt]\end{aligned}$$Step 3 : Multiply the boxed numbers together:
$$ GCD = 5 $$This solution can be visualized using a Venn diagram.
The GCD equals the product of the numbers at the intersection.