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Expert: Robi Bhattacharjee - 9/9/2008


Question
Using the numbers 2,4,9,6,7,3, Digits appear only once in an answer.  each answer may not use all digits.  "The difference between these two 3 digit numbers with 263."
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Answer
Hello David,

I'm not too sure what you are asking, but I will answer the question I think you are asking.

If you are asking make two three digit numbers that have a difference of 263, then the answer is the following.

For starters, you know that the first digit of both numbers should have a difference of 2 or 3. So maybe 9 and 7.

This didn't work out. So basically, I will keep trying out values until I get something that works.

So I won't say everything I tried out, but I eventually thought of the fact that the last digits of the numbers could be 2 and 9. 2- 9 is -7 but 12 - 9 is 3. So if I experiment with that. I get

642 - 379 = 263.

So the numbers are 642 and 379.

Basically to sum it up, how you do this problem is you notice that the last two digits have to have a difference of 3, and one way to do this is 12 - 9 and you carry the 1. So this is sort of a trial and error problem.

I hope this helped,

Robi

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Robi Bhattacharjee

Expertise

I can answer a variety of questions on mathematics. Questions on trigonometry, calculus(preferably single variable), algebra, geometry, and number theory will be answered. I cannot answer questions on abstract branches of mathematics such as group theory. I also cannot answer questions on statistics. In number theory, I can answer questions on congruences, prime numbers, units, functions, and the riemann-zeta function.

Experience

I have studied advanced math my entire life. I started calculus in sixth grade. I have attended numerous math competitions and I am attending math organizations such as the San-Diego math circle. Also, this year I have been invited to the USAMO which is a prestigious math competition (Every year the USAMO invites 500 students from across the USA to participate in this competition. The top 6 go to represent the USA in the International Math Olympiad).

Organizations
I am in the San Diego Math Circle

Education/Credentials
I am entering high school and have received a perfect score and the STAR test 5 times in a row. I also have gotten recognitions in the AMC 10, AIME, Math Counts, and ARML. Additionally, I have won the San Diego Math Olimpiad twice in a row.

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