The display of the odometer in my car showed a number of five consecutive, decreasing digits. My mind wandered off. It was a nice number, of course. It was also clear what the next number with decreasing consecutive numbers would be, and how many kilometers I would have to drive. But what would be the next number that consisted of consecutive digits, and which also would be a prime number?
You can check your solutions here
Which one of the numbers does not belong in the following series?
3, 4, 8, 9, 10, 18, 19, 38
You can check your solutions here
What number comes next in the following sequence?
56789
51317
548
…
You can check your solution here
1) The coffee stain
**
When I visited an old friend of mine, with his laptop out of order, he had just completed a simple multiplication with pencil and paper. Unfortunately, I spilled some coffee over it. Can you pelase help him to complete the multiplication again?
2) The missing digits puzzle
**
In his “Cyclopedia of 5000 Puzzles, tricks and conumdrums” American puzzle master Sam Loyd presented the following puzzle:
Sam Loyd tells a long story about Mormon rock, and in his reprint Martin Gardner skipps this part. I will not follow his example in order to preserve the history, but I do not want to offend anyone, and one should take notice that Sam Loyd was also a master in inventing stories, as can be illustrated with the example on the Swiss flag. Don’t take anything he tells seriously.
Once again discussion has been revived concerning the meaning of the hieroglyphic numbers engraved on Mormon Rock. Mormonism originated only so far back as 1830, so if these weather beaten figures have anything to do with the Latter Day Saints there should be thousands of persons qualified to tell all about them, unless, as some claim, they pertain to the hidden mysteries.
The Mormons migrated in 1838 From Kirtland, O., to Nauvoo, the “City of Beauty” in Illinois and to Salt Lake in 1848. When they left Nauvoo they boasted that their line of march would be twenty four miles long, and was te be headed by a printing press to issue the daily orders of the prophet. It was stated that they were divided up into numerous companies, each one headed by one of the prophet’s wives, and the mysterious fiugures on the Mormon Rock were supposed to give the number of pilgrims in each division.
The figures look like a sum in division engraved upon a sandstone rock. Most of the numbers are illegible, but as some are sharp and clear it is to be assumed that the others were erased maliciously or for a purpose. It is now claimed that either through accident or design the eight legible numbers furnish a key to the mystery, and that the whole is a sum in long division which tells just how many pilgrims marched with each division, and incidentally gave a clue to the number of the prophet’s patrimonial ventures.
It is a remarkable coincidence that the remaining numbers furnish a cluse which easily solves a most interesting historical puzzle, for if you write down the sum in long division, mixing stars with the legible figures as shown, you should speedily be able to guess the numbers which have been erased so that the sum will prove. It reaaly looks as if there should be scores of correct answers, and yet so far as I am aware, but one satisfactory restoration of the missing numbers has been suggested.
Just in case the illustration is not clear, here is a more abstract image of the problem:
3) Dudeney
**
In his “536 problems” British puzzle master Henry Dudeney presents the following problem:
He tells it was send to him by the reverend E.F.O. It is, he tells, the first example he has seen of one of those missing-figures puzzles.
You can find these and other puzzles like these in the second edition of my e-book with numbers puzzles.
A Sojuko can be considered as part of the Sudoku family in the sense that the 3×3 square contains each of the digits 1 to 9 exactly once. Some of the digits have been omitted, and the puzzle is to restore the missing digits. As clues four circles are given, holding the sum of the numbers in the squares around them. The solutipon techniques however are reminiscent of Kakuro.
Sojuko number 1
Sojuko number 2
>
I found them in “Terdege”, a puzzle add-on of the newspaper “Reformatorisch dagblad”.
Make the equation in the picture above correct. To do so, you may freely move the digits around. You may not add other stuff such as plus signs, multiplication signs, and so on.
Recently I purchased “Logic Brain Teasers”, published by Mensa. There was a puzzle on the back cover and while attempting to solve it as a family during dinner, the idea for this puzzle was born.
You can check your solution here
You are welcome to remark on the puzzle: its wording, style, level of difficulty. I love to read your solution times. Please do not spoil the fun for others by listing the solution.
I do offer my apologies that the puzzle above does not carry a christmas theme, as I had intended. I had two puzzles in mind, but in one I made an error in my calculation and for the other I had insufficient infomation on its origin.
Christmas time is something special in many parts of the world. For some, these are happy days with the family. For others, it’s just a few days off. For me, as an orthodox christian, it is a time of celebration.
Celebration, because where we humans develop irritation, dislike and even hate, God has come to offer a possibility of peace.
Celebration, becuase where we suffer poverty, He has come to share his richness with us.
Celebration, because where we suffer bondage, He has come to set us free.
Celebration, because the God, who is greater than our imagination can comprehend, chose to be born as a small and vulnerable baby.
I wish that you may enjoy the Christmas days and may experience a little bit of the peace, freedom, and richness he wishes to give us.
What is the smallest number of which the square ends with three identical digits? And indeed, 0 is excluded as a solution.
This is a slightly simplified version of a problem published as perplexity 466 by Henry Dudeney in The Strand magazine august 1919.
You can check your solution here
Crosswords are among the worlds most printed and devised puzzles. And though they are puzzles with words, they are not language puzzles and they can be fairly easily generated once you have a large dictionary in electronic form available.
But Crosswords are so common place I have thus far avoided them in this blog. There are several number variants however, and the one presented here is geared towards math buffs.
| Horizontal | Vertical |
| 1 square with identical first and third digit 3 fibonacci number 5 perfect number 7 number of cards in bridge 9 happy number 10 catalan number 11 monodigit number 12 lucas number 14 happy number 16 narcistic number 18 circular prime 19 fibonacci number |
1 factorial number 2 prime number 3 fourth power 4 catalan number 6 multiple of 11 8 third power 9 perfect number 12 third power and a square 13 fibonnacci number 15 triangular number 16 fermat prime 17 square |
You can check your solution here
1) Cross out 5×5**
In the square below, cross out numbers until the sum is 15 in every row and column:
2) Cross out 7×7**
In the following square, cross out numbers till you the sum is 15 in every row and column:
This type of puzzle was probably invented by Rita Hovestad or Marenke Wiersma, editors of Sanders Brainteaser no 5.
You can check your solution here for no 1 and here for no 2
A new puzzle is published every friday. The solution is generally published one week later. I welcome your reactions on these puzzles: are they too easy, too difficult, are trhere any multiple solutions? How long did you need to solve it?
justpuzzles 