Monthly Archives: December 2016

Find a 4 digit number


Number**/*****
Find a four digit number abcd such that
– abcd is a prime number,
– a+b+c+d = 10,
– the sum of the digits of ab*cd equals 7.

You can check your solutions here.

New puzzles are published at least twice a month on Friday. 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.

On the first day of Christmas…


1) On the first day of Christmas**/*****
On the first day of Christmas, my true love brought to me:
On the first day of Christmas
My true love gave to me
A partridge in a pear tree

On the second day of Christmas
My true love gave to me
Two turtle doves
And a partridge in a pear tree

Thus go the first two couplets of a traditional Christmas song. Question is:
Haw many things did my true love give me over these 12 days? (counting the partridge in the pear tree as one item)

You can check your solutions here

2) On the second day of Christmas**/*****
Yeah, in puzzle 1 above you had the classical song. But in puzzle land, everything is different.
In puzzle land, on the second day of Christmas my true love brought me this puzzle:

“This puzzle consists of @ letters”

With what number (spelled out, of course) should @ be replaced to be true?

You can check your solutions here

3) On the third day of Christmas**/*****
On the third day of Christmas, my true love brought to me this puzzle:

“This puzzle consists of @ vowels and # consonants”

Again, by which numbers, spelled out, should @ and # be replaced to yield a true sentence? Please note that “y” is counted as a vowel.

You can check your solutions here

New puzzles are published at least twice a month on Friday. 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 three stars.

Christmas puzzle


The Dutch equivalent of the CIA & NSA is called the AIVD. One of their departments has been compiling a set of Christmas puzzles for decades, and since a few years these puzzles are published on the internet. You can download the 2016 version.

Though most puzzles are language dependent (in Dutch), there are some which at least on the surface do not seem to require knowledge of the Dutch language.
Here is a list of the exercises and the translation of the exercises/hints of the puzzles for which you probably don’t need to know dutch:
2. Elementary: Which one is out of order?
4. What is the next number in each of the two series?
10. Two persons on a ferry are comparing two rows. One counts differences, the other comparisons. They arrive at the following series. What are the next numbers?
23. Sequences. What are the next three items in the lists?
I warn you, they have the reputation to be pretty tough. 100 points can be earned each year. Every year, people crack all exercises, but in no year did one person all problems.

Thanks to our daughter Joella, who solved puzzle 1b, I can offer you the puzzle below. Which number should replace the question mark:
?
position
drawback
frazzled
bragging
phishing
eternity
sickness

No, I don’t intend to publish the solutions. But I guess the solutions will be published here

cryptarithm: worship


Alphametic**
This weeks puzzle has a christian theme. In this alphametic, replace every letter with a digit. The same letter always represents the same digit and identical digits have always been replaced by the same letter:

Cryptarithm 2016-06-11 nr 1 exericse

You can check your solutions 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 three stars.