/* From """ My 10 year old brother gave me this question and I can’t solve it. As a 17 year old it is embarrassing. But can any one of you solve it? """ Via From MindYourDecisions "An interesting homework puzzle" """ This problem was shared on Reddit Maths with the title “My 10 year old brother gave me this question and I can’t solve it. As a 17 year old it is embarrassing. But can any one of you solve it?” In each diagram, the numbers combine in the same way to make a valid equation. What number is missing? """ The Reddit thread: https://www.reddit.com/r/maths/comments/17amw0n/my_10_year_old_brother_gave_me_this_question_and/ 2 3 2 9 2 ? 6 4 4 32 12 24 After forcing the solutions to be 6: AllGood: [program = (2 * A - (5 - A)) * (B * (B / C)),res = 6.0,count = 1] resultMap = [6.0 = 1] Simplification from Mathematica: In[1]:= (2 * A - (5 - A)) * (B * (B / C)) 2 (-5 + 3 A ) B Out[1]= ------------- C AllGood: [program = B * B / C / (A * ((2 - A) / B) + 1),res = 6.0,count = 1] AllGood: [program = B * B / C + A + A / (1 - A),res = 6.0,count = 1] Without forcing the solution to 6, other solutions are found (though 6 was not found): resultMap = [2.33333 = 6,2.33333 = 6,54.0 = 5,9 = 5,27.0 = 4,81 = 3,27 = 3,9.0 = 2,4.0 = 1] AllGood: [program = (C - 4 * (5 * (8 - 10) + 2)) * (B / B / C),res = 2.33333,count = 565] [program = (C - 4 * (5 * (8 - 10) + 2)) * (1 / C),res = 2.33333,count = 513] [program = 1 / C * (C - 4 * (5 * (8 - 10) + 2)),res = 2.33333,count = 489] [program = (B - 3) * (6 / A),res = 27.0,count = 448] [program = 9 - 7 * (1 * A - 2),res = 9,count = 447] [program = (C - 4 * (5 * (8 - 10) + 2)) * (9 / (9 * C)),res = 2.33333,count = 412] [program = 6 / A * (B - 3),res = 27.0,count = 364] [program = B / B / C * (C - 4 * (5 * (8 - 10) + 2)),res = 2.33333,count = 346] [program = (C - 4 * (5 * (8 - 10) + 2)) / C,res = 2.33333,count = 342] [program = 9 * (B / B) - 7 * (1 * A - 2),res = 9.0,count = 321] [program = (B - 3) * (B / 2),res = 54.0,count = 305] [program = 9 / (9 * C) * (C - 4 * (5 * (8 - 10) + 2)),res = 2.33333,count = 301] [program = 1 + 8 - 7 * (1 * A - 2),res = 9,count = 293] [program = 4 + 5 - 7 * (1 * A - 2),res = 9,count = 281] [program = 8 + 1 - 7 * (1 * A - 2),res = 9,count = 212] [program = B / 2 * (B - 3),res = 54.0,count = 203] [program = (C - 4 * (5 * (8 - 10) + 2)) / (C / 1),res = 2.33333,count = 141] [program = (5 - A) * (B - 3),res = 27,count = 123] [program = 9 * 1 - 7 * (1 * A - 2),res = 9,count = 112] [program = (B - 3) * (5 - A),res = 27,count = 105] [program = (B - 3) * (A + B - 5),res = 81,count = 64] [program = (B - 3) * (B / (3 + 7 - 9) / 4 * 2),res = 54.0,count = 60] [program = B / (3 + 7 - 9) / 4 * 2 * (B - 3),res = 54.0,count = 44] [program = B / (3 + 7 - 9) / 4 * 2 * (B - 9 + 6),res = 54.0,count = 23] [program = 10 - C / 4,res = 4.0,count = 14] [program = (C - 4 * (5 * (8 - 10) + 2)) / (C * 1),res = 2.33333,count = 6] [program = (C - 4 * (5 * (8 - 10) + 2)) / (1 * C),res = 2.33333,count = 6] [program = (B - 3) / (A / 6),res = 27.0,count = 6] [program = (C - 4 * (5 * (8 - 10) + 2)) / (C * C / C),res = 2.33333,count = 2] [program = 9 / 1 - 7 * (1 * A - 2),res = 9.0,count = 2] [program = (C - 4 * (5 * (8 - 10) + 2)) / (C * (1 * 1)),res = 2.33333,count = 1] [program = 6 / A * (B - 9 + 6),res = 27.0,count = 1] [program = (A + B - 5) * (B - 3),res = 81,count = 1] [program = (A + B - 5) * (B - 9 + 6),res = 81,count = 1] [program = (5 - A) * (B - 9 + 6),res = 27,count = 1] */ data(mind_your_decision2,Data,Vars,Unknown,Ops,Constants,MaxSize,Params) :- Data = [ [[2,6,4],9], [[3,4,32],2] % , [[2,12,24],6] % force a solution ], Ops = [+,-,*,/], % Ops = [pow_restricted_limit_30,+,-,*,/], % Ops = [+,-,*], Constants = 1..10, Vars = ['A','B','C'], Unknown = [2,12,24], MaxSize = 31, Params = new_map([num_gens=1000, reset_timeout = 600 % reset problem after reset_timeout seconds ]).