The sum is calculated as follows:

$3 + 0.02 + 1.9 = 4.92$

The result is:

$\boxed{4.92}$

Would you like a more detailed breakdown? Here are five related questions for further exploration:

1. How can decimal numbers be added more easily?
2. What is the difference between adding integers and decimals?
3. How do you convert decimals to fractions for addition?
4. Can you demonstrate the addition of decimals using a number line?
5. How is addition applied in real-world scenarios, such as finances?

Tip: Always align decimal points to ensure accuracy when adding or subtracting decimals.