(1/10)18 - (1/10)20 = ?
99/1020
-0.2
1/10 is = 0.1 so (1/10)18=1.8 lly (1/10)20=2.0 so 1.8-2.0=-0.2 answer is = -0.2
(1/10)^18 - (1/10)^20 = 1/(10^18) - 1/(10^20) = (10^2 - 1)/(10^20) = 99/(10^20)