On 2018, june 29, I published a post with two clock problems. Here you find two more problems.
1) Clock 1**/*****
2) Clock 2**/*****
You can check your solutions here
New puzzles are published at least twice a month on Fridays. Solutions are published one or more weeks later. You are welcome to comment on alternate solutions, the level of difficulty, and so on.
A few weeks ago I mentioned Catriona Shearer and her twitter account with geometry puzzles.
She has collected all her geometry puzzles of the last few months in some powerpoint sheets, which you can find here.
A couple of years ago I posted the problem of four fours.
Recently I stumbled upon Gene Wirchenko’s Blog, and he had s similar problem.
Here is a variation of his problem. Combine 2, 3 and 5 to make all the numbers 0-22. Use each of the three digit exactly once, but you are free to use addition, multiplication, division, subtraction, brackets, exponentiation and factorial as often as you like.
For those of you who are not familiar with factorials a short reminder:
0! = 1
1! = 1
2! = 2*1
3! = 3*2*1
4! = 4*3*2*1
etc.
You can check your solution here
New puzzles are published at least twice a month on Fridays. Solutions are added after several weeks.
On June 8, I published a couple of figures which can be made with the plastic snake puzzle of Clown Games, and 5 years ago I wrote about another one.
My wife Jos and our daughter Margreet made a cpouple of new figures, which are too goof not to share with you, especially as some of the recent ones are real gems.
This puzzle was inspired by a puzzle in one of the many Mensa puzzle books, “”Logic brainteasers”, by Philip Carver and Ken Russell.
You can check your solution here
If you think that most of the original puzzles types are published in magazines or on blogs like this one, you may be wrong. In my experience, I discover most new puzzle types in apps.
Recently my wife asked me for assistance in solving a level of Frog Logic. It was a pretty tough level to jump into, and it took a couple of weeks before I decided to install it myself.
Let me post a screenshot of a level:
The object is to clear all leaves. The frog jumps from leave to leave, sinking the leaf it departs from. It may jump only horizontally and vertically, not diagonally. It may jump straight ahead, or turn 90 degrees, but it may not turn 180 degrees. The puzzle is finished if all leaves have been visited.
I can wholeheartedly recommend this app: tough puzzles, built up gradually, simple rules, original puzzle type, and not too many adds.
You can check your solutions here
| Aspect | Score (1=least – 5=best) | Remarks |
| Rules of puzzle type clear | 5 | Original puzzle type |
| Toughness | 4 | Good challenges, gradually becoming tougher. |
| Price / adds | 5 | Free, and not too many adds |
| Number of puzzles | ? | Not sure how many puzzles there are |
I hope to review more puzzle apps in the future.
1) Three squares**/*****
On twitter I found the account of a very kind and smart lady called Catriona Shearer, who poses a lot of very nice and original math problems. One problem is reproduced here with her permission. In the figure above, the sides of the three squares are three consecutive integers. The length of the black line is 4√10.
What’s the total area?
You can check your solution here
2) Four squares***/*****
The puzzle above inspired me to the following puzzle:
The length of the sides of the three smaller squares are all natural numbers – integers if you prefer that term. The length of the side of the big square is 6√10.
What is the size of the three small rectangles?
New puzzles are published at least twice a month on Fridays. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to 5 stars.
You can check your solution here
1) Adding a nine***/*****
22 = 4. Writing a 9 after it, I get 49 which is 72
42 = 16. Writing a 9 after it, I get 169 which is 132
What is the next square number, which, when adding a 9 after the number, is a square?
You can check your solution here
New puzzles are published at least twice a month on Fridays. Solutions are published after one or more weeks. You are welcome to remark on the difficulty level of the puzzles, discuss alternate solutions, and so on. Puzzles are rated on a scale of 1 to 5 stars.
Resolf puzzles consist of four triangles, with three numbers at the corners of each triangle and the sum of the three numbers in the center.
I first encountered them in a publication by Sanders Puzzles.
An example of a solved resolf looks like this:
Nr 1*/*****
Use the numbers listed below the triangle to make the sums
Sanders puzzles regularly also uses multiplcation:
Nr 2**/*****
And one can extend this machanism to all 40 basic arithmetic operations:
Nr 3***/*****
You can check your solution here
New puzzles are published at least twice a month on Fridays.
justpuzzles 