What is the value of 9991 × 10009?
A. 99999099
B. 99999819
C. 99999919
D. 99999019
Answer: Option C
Solution (By Examveda Team)
9991 × 10009= 9991(10000 + 9)
= 99910000 + 89919
= 99999919
Alternate solution
9991 × 10009
= (10000 - 9)(10000 + 9)
= (10000)2 - (9)2
= 100000000 - 81
= 99999919
This Question Belongs to Arithmetic Ability >> Number System
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