If 10 was as easy as black on white and 0 was invisible as a solid color, I'd rate this graphic as a 6.5/10 in difficulty. You can clearly read it in less than a second, but you will probably spend the rest of the second and part of the following second looking for the edges of the letters and double checking it says what you thought it said and not something else. They are somewhat dull reds and greens, but they are visible. If you are having too much trouble then perhaps your phone display settings may need adjusting.