Hexadecimal Color Value

Question

When I'm answering the Color Code quiz. I face so much difficulty to choosing correct answer.
Can you give any solution?

Answer 1

Training yourself to know what shifts in number does. I suggest using this site. Set two colors to 0. Modify the 3rd from 0 to ff in 40 increments. Then, increment to first two up 40 and repeat modifying the 3rd. Repeat as needed until you have the concept learned.
https://www.w3schools.com/colors/colors_picker.asp