A prime number is a number that can only be divided by 1 and by itzelf. Examples are 2, 3, 5, 7, 11, 13 and so on. You can find the first 1000 prime numbers here.
Now here is a quicky: write 1000 as the sum of as many different primes as possible.
You can check your solutions here
A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.
Suppose we have a tetrahedon, and cut of all 4 corners. That gives us a new shape with new corners, from which we cut off again all corners. How many corners does the resulting figure have?
A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.
You can check your solutions here
This week a colleague brought some cake for his birthday. He didnt want to tell his age, but he did reveal that he and his daughter together were 46 years old, and that in eleven years he would be thrice as old as his daughter.
What are their ages?
You can check your solutions here
The Dutch reformed-christian ‘Reformatorisch Dagblad’ twice a year publishes an extra puzzle issue for its subscribers. This weeks puzzle type is 1-8, invented by Marijke Balmaekers, and published in the childrens section of the ‘Vakantie Doe Boek’ of the reformatorisch Dagblad.
The numbers one to eight have been arranged in a 5×5 grid in such a way that:
Example:
number 1
number 2
number 3
Don’t worry, this blog is not turning into a crosswords puzzle blog, and neither is it changing into a word puzzl;e blog.
But every now and then there is a nice variation on a traditional theme, and for programmers there is a nice variation using regexp here
In an upcoming post I intend to go into depth on numerical crossword variations,
For now: Have fun!
Yesterday, that is, the day before I wrote this, I received the English translation of Boris Kordemsky’s “Russian Puzzles” (Matematicheskaia smekalka, which translates as ‘Math savvy’), edited by Martin Gardner. It was first published in 1956. In the first few chapters it contains many old chestnuts, sometimes disguised in a new coat. Though I am not a big fan of Martin Gardner, he did preserve the Russian atmosphere well. Many of the familiar puzzles can also be found in the works of Henry Dudeney and Sam Loyd. Alas Martin Gardner left out a series of problems towards the end related to number theory (‘too difficult for the american public’). Now that that sounds like two insults :).
It inspired me to make a small variation:
“I will plough this field at an average of 200 furrows a day,” Pjotr told his comrades in the Kolkhoz. And indeed he started out right away the next day. He set off relaxed; making just 100 furrows a day on the first 1/3 of the field , but he could blame some initial problems for thet. Once the initial problems were solved, he was able to plough at a speed of 200 furrows a day for the middle 1/3 of the field.
He realized that he was still lagging behind on his promise and made some small improvements, enabling him to complete the final third of the field at 300 furrows a day. At the next meeting of the kolkhoz he told with satisfaction that he had lived up to his promise. The party administrator however denied his claim:
“Tovarisj Pjotr,” he said, “I think you err.”
Who was right?
You can check your solutions here
A new puzzle is posted every Friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.
First of all I wish each and everyone of you a happy and healthy 2016!
Having said that, can you tell me what the last two digits are of 2016^2015?
You can check your solution here
“It was during the Russian Civil War, ” Captain Abromovitch told his great grandchildren, “That I was ordered to take my ship, the Asbestos, down the river from Astrakhanitch to Cosmovitch. It was a valuable package I had to transport, and a dangerous mission as well, as the Tzarists still controlled Borovitch between Astrakhanitch and Cosmovitch. In Borovitch, the Tzarists held control of the Berilyum, a sistership of my Asbestos. Both had the same speed of 5 miles per hour on a lake without any current.”
He took a sip from his orange juice, and continued:
“They had a spy in Astrakhanitch, and this enabled the Berilyum to leave Borovitch to intercept me the minute I left Astrakhanitch with my Asbestos. Steaming upstream, of course the Berilyum went slower than my Asbestos steaming downstream, so we didnt meet in the middle between the two towns, but at a point closer to Borovitch than to Astrakhanitch. Having several soldiers on board, while I had none, they immediately seized my ship and brought us to Astrakhanitch.”
If the distance between Astrakhanitch and Borovitch is 20 miles, how long did it take the Tzarists to intercept the Asbestos?
You can check your solutions here
A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.
This week I’ve got a quickie for you.
Last week I took an online certification exam. It was an open book certifiction, and I was free to consult the website and course map as often and as long as I wanted. Some types of questions scored 3 points, others scored 5 points.
My result was:
You scored 201 points out of 223 total possible points.
You answered 45 out of 51 questions correctly.
How many 5-point questions and how many 3 point questions did I miss?
You can check your solutions here
A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.
I had to tile the floor of a room which was to 2 meters long and 2 meters wide. I had boards of 20 cm wide and either 1.60 or 1.80 meter long. How many boards do I have to saw so that I can cover the entire floor?
You can check your solutions here
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