(1/10)18 - (1/10)20 = ?
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99/1020
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0.99
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99/10
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none of these
Reveal answer
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A
Correct answer
Explanation
(1/10)^18 - (1/10)^20 = 10^(-18) - 10^(-20) = 10^(-20)(10^2 - 1) = 10^(-20) × 99 = 99/10^20. Option A represents this as 99/10^20 (where 1020 denotes 10 to the power of 20).
AI explanation
(1/10)^18 minus (1/10)^20 can be rewritten with a common denominator of 10^20: that's 100/10^20 - 1/10^20 = 99/10^20. The listed option is shorthand for 99 over 10 raised to the 20th power, which is the correctly simplified difference of the two very small fractions.