Monthly Archives: May 2013

Making 24 with the days of the Month : June, 2013

  Today is May   31,   2013,   that is, 2013-5-31,   try to make   24   of   (20,   13,   5,   31) One possible answer:                ceiling(√31)   +   floor(√13)   +   … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged | Leave a comment

2-digit Num3ers | DigitSum and DigitProduct

  Let   ab   be a 2-digit number DigitSum (ab)   =   a   +   b DigitProduct (ab)   =   a * b N   =   10*a   +   b   –   (a … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged , | Leave a comment

Sums and products of pairs of num3ers are squares

                                                         a   +   b   =   x^2                                                        a   *   b    =   y^2     Here are the first few examples   2^2 = 2 + 2 2^2 = 2 * 2 … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged , , | Leave a comment

5-digit num3ers divisible by 3-digit contained in the middle of the num3ers

  11371                                        11371 / 137  =  83 11398                           … Continue reading

Posted in Math Beauty | Tagged , | Leave a comment

Concatenation | x^4 * y = x || 4 || y

  Older post:   Concatenation |   x^2 * y   =   x || 2 || y                                              x^4   *   y   =   x || 4 || y   Here are few solutions: 3^4   … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged | Leave a comment

2-digit num3ers expressible as 10*a + b – (a^2 + b^2)

To find a 2-digit number ab such that ab   –   (a^2 + b^2)   =   N,    N   =   10,   11,   12,   13   …   ,   99   10   … Continue reading

Posted in Math Beauty | Tagged | Leave a comment

Concatenation | x^2 * y = x || 2 || y

                     x^2   *   y   =   x || y                    x^2   *   y   =   x || 2 || y   For example, 3^2   *   375   =   3375   … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged | 1 Comment

x^2 + k = y^3

                                       x^2   +   k   =   y^3   If   k = 0 Trivial cases:    x = y = 0    and    x = y = 1 8^2   =   64   = … Continue reading

Posted in Number Puzzles | Tagged | 1 Comment

Numbers whose fifth power is the sum of 5th powers

  12^5   =   11^5   +   9^5   +   7^5   +   6^5   +   5^5   +   4^5     Can you find other 5-th powers that can be expressed as the … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged | Leave a comment

Concatenation | (-x + y)^2 = x || y

To find integers N such that                          N   =   (-x + y)^2   =   x || y                          N   =   (x – y)^2   =   x || y   For example, 364^2   = … Continue reading

Posted in Math Beauty, Number Puzzles | Tagged | Leave a comment