Problem:
1,000,000,000,000−777,777,777,777=
Answer Choices:
A. 222,222,222,222
B. 222,222,222,223
C. 233,333,333,333
D. 322,222,222,223
E. 333,333,333,333
Solution:
Write the problem vertically and compute the difference:
1,000,000,000,000−777,777,777,777222,222,222,223​​
OR
What must be added to 777,777,777,777 to get 1,000,000,000,000? From the right, one adds a final digit of 3 and then eleven 2′s.
Answer: B​.
The problems on this page are the property of the MAA's American Mathematics Competitions