Well let's convert all these values out of standard form first:
2x10^-2 = 2x0.01 = 0.02m = 2cm
2x10^0m = 2x1 = 2m
2x10^-1m = 2x0.1 = 0.2m = 20cm
2x10^1m = 2x10 = 20m
Based on that, we know that 20cm is roughly equivalent to a basketball (at least it's closer than all the other values), so the answer is therefore 2 - 2x10^-1m
