Math Question of the Week

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http://mathcontest.olemiss.edu/

Elementary Brain Teaser

12 Sevens - November 11, 2013


What will be the digit in the tens place of the sum of the following expression:   7 + 77 + 777 + 7777 + ... + 777777777777

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Middle School Madness

Red Corner Checker - November 11, 2013

 

You are given a 5 x 5 checkerboard with red and black squares.  If each corner square is red, what percent of the board is black?

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Algebra in Action

100th Group - November 11, 2013

 

Group the consecutive counting numbers as follows: (1), (2, 3), (4, 5, 6), (7, 8, 9, 10), . . .  Note there is one number in the first group, two in the second group, three in the third, etc.  Determine the sum of the 100 numbers in the 100th group?

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Problem of the Week

10 Digit Call - November 11, 2013

 

A typical telephone number in the United States used to be 7 digits.  While you can still use a seven-digit code in most areas, a multitude of regions have begun using ten-digit telephone numbers. If the entire country goes to a ten-digit telephone, exactly how many different ten-digit telephone numbers will be available such that the first digit cannot be a 0 or 1 and the fourth digit cannot be a 0 or a 1?