Listed below are problems from Problem of the Week where 50% or less of the responses were correct. Test your knowledge by submitting answers to these past problems. Remember, you can still submit answers to any past problem. We will respond to your submission but your name will not be added to the list if your answer is correct.



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• 	15%	Two Scoops of Ice Cream	September 03, 2007
  	16%	Next Problem	August 20, 2012
  	16%	Roll That Die	September 27, 2010
  	18%	10,000,000,000	February 23, 2009
  	19%	Middle Three Digits	December 03, 2007
  	19%	Code Work	February 04, 2008
  	22%	Less Than 500	September 24, 2012
  	24%	Enormous Sum	November 03, 2008
  	25%	Nine-Digit Binary	November 08, 2010
  	25%	Seven Factorial	May 03, 2010
  	26%	Tic Tac Toe	November 26, 2007
  	26%	Triple ABC	September 10, 2012
  	26%	Eighty-Five Four Digit Numbers	November 12, 2007
  	27%	Dodecahedron	January 24, 2011
  	27%	Cracked Tile	December 04, 2006
  	28%	35 Only Once	September 12, 2011
  	28%	Fifty-one Factorial	September 24, 2007
  	28%	Green Marbles	November 28, 2011
  	29%	Seven Digit Pair	September 17, 2012
  	30%	Up and Down Numbers	January 14, 2008
  	30%	2502254	October 01, 2012
  	30%	EDUCATION	November 15, 2010
  	30%	X Greater Than Y	March 31, 2008
  	31%	Next in the Line	June 22, 2009
  	31%	Dividing by Perfect Squares	July 21, 2008
  	32%	Without Sevens	August 13, 2007
  	32%	Consecutive N	September 26, 2011
  	32%	Red or Blue Cube	December 03, 2012
  	33%	Sum of All Primes	September 15, 2008
  	33%	Sum Billions	April 21, 2008
  	33%	Column Four Puzzle	April 28, 2008
  	34%	Open Lockers	March 22, 2010
  	34%	Wheat Hens	September 22, 2008
  	34%	Triangles and Cubes	November 01, 2010
  	35%	4064465	April 30, 2012
  	36%	Divisible Perfect Squares	April 25, 2011
  	36%	Difference of Three Primes	March 10, 2008
  	36%	Factorial Remainder	November 27, 2006
  	38%	2003 Expansion	July 07, 2008
  	38%	Seventeen Cent Contest	August 31, 2009
  	38%	How Big Is A Billion	January 08, 2007
  	39%	Hot Cocoa	September 08, 2008
  	39%	Carnival Chance	January 30, 2012
  	39%	Eight Knights	September 03, 2012
  	40%	Trapezoid	January 29, 2007
  	40%	Even Ten By Ten	January 28, 2013
  	40%	101st Group	October 17, 2011
  	40%	How Many Triples?	November 09, 2009
  	41%	Year 2040	November 16, 2009
  	41%	Month of the Planets	February 18, 2008
  	41%	Unknown Area	February 02, 2009
  	41%	Wooden Blocks	March 25, 2013
  	42%	Odd Ordered Pair	September 10, 2007
  	42%	Not Multiples of Eleven	March 19, 2012
  	42%	Reciprocal Difference of One	July 14, 2008
  	43%	Driving to Work	August 25, 2008
  	43%	Chess Anyone	February 08, 2010
  	43%	Ten Number Set	February 04, 2013
  	43%	Ten Digit Square	April 23, 2007
  	44%	Vanilla Ice Cream	April 20, 2009
  	44%	Last Monday	October 19, 2009
  	44%	Units Digit Dividing	April 07, 2008
  	45%	As The Crow Flies	June 04, 2007
  	45%	Tennis Anyone	February 22, 2010
  	45%	Four Thousand Digits	January 28, 2008
  	45%	One Through Five	November 05, 2007
  	45%	Four Digit Evens and Odds	June 08, 2009
  	46%	Faster Than A Speeding Train	August 24, 2009
  	46%	Simplify Powers	June 15, 2009
  	46%	7-11	March 09, 2009
  	46%	199 Numbers	March 12, 2007
  	46%	Dividing Prime	October 10, 2011
  	46%	Circle, Square, and Triangle	January 16, 2012
  	47%	Column to Rows	February 01, 2010
  	47%	Factorials Cubed	September 01, 2008
  	47%	The Monuments	September 14, 2009
  	47%	Factorial Series	February 13, 2012
  	47%	Sum of Consecutive Numbers	March 07, 2011
  	48%	A+b+c+d	December 11, 2006
  	49%	Water Tank	July 13, 2009

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