Issue 10 
Season 1. July 30,2005
23. Emptymino (8 and less)
Place all 12 pentominoes in a rectangle of maximal area, so that no pentomino can fit in the areas left empty. You can rotate and/or reflect the pentominoes.
Example:
Answer key: first write down the area of the rectangle, then describe it row by row, replacing emtpy cells with “O”s. For the example the answer would be: 25: OYYYY, OOYOO, OXOZZ, XXXZO, OXZZO. Best answer brings 8 points; each next answer will bring one point less.
Answer:
123: OIO, OIO, OIO, OIO, UIU, UUU, OOO, OWW, WWO, WOO, OYO, OYY,
OYO, OYO, ZZO, OZO, OZZ, OTO, OTO, TTT, OOO, OFF, FFO, OFO, ONO,
ONO, ONN, LLN, OLO, OLO, OLO, OXO, XXX, OXO, OPO, PPO, PPO, OOV,
OOV, VVV, OOO
24. NICE (8 and less)
Make the smallest number of turns to reach the situation where in every row from left to right and in every column from top to bottom all the letters were in alphabetical order. For one turn you can rotate any rectangular area of table by 180 degrees. Square areas can be rotated by 90 degrees as well. All allowed letters given below are in alphabetical order. Usage of other signs during the process is allowed.
Example:
Answer key: fi rst write down the number of turns, then describe them all, giving the row and column of top left corner of the rotating area, its width and height, and, fi nally, direction (“R” for clockwise turn by 90 degrees, “L” for such counter-clockwise turn, for 180 degrees turn don’t write the direction). For example, after turn “1233L” the table would look like this: NWWW, NUUU, NHHH, NICE. Best answer brings 8 points; each next answer will bring one point less.
Answer: 9:1144,1121,2113,3142,2233R,3212,3231,1312,3121
25. Glued (8 and less)
Make the math expression equal to 12345, using minimal number of digits and arithmetic signs (+,-, /, *), so that breaking this expression into 5 pieces gives new expressions equal to 1, 2, 3, 4 and 5 in order. Each piece must have at least one arithmetic sign. Two arithmetic signs cannot follow each other succesively. All digits from 0 to 9 must be used in the expression. Pieces can start only with digit or "minus". The operation priority is usual. There cannot be any parentheses.
Answer key: fi rst write down the number of characters in the expression (both digits and arithmetic signs), and then write it completely, separating pieces with “|”-signs. Example for the number 123 (not all digits are used): 11: -1+2|09-7|9-6. Best answer brings 8 points; each next answer will bring two points less.
Answer: 19:15-6-8|9-7|0+3|1*4|03+2
All solutions by Frederic Gloannec.
