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Today’s puzzles are aimed at helping Ukraine.

They are written by the Grabarchuk family, who are one of the most original and prolific puzzle creators in the world. Originally from the western Ukrainian town of Uzhgorod on the Slovakian border, the family moved to the United States in 2013 after gaining international acclaim for their puzzle books, websites and apps. Computer legend Donald Knuth says clan father Serhiy Grabarchuk “has my vote as the current global puzzle winner. His works are particularly beautiful, instructive and fulfilling.

Since the start of the war, the Grabarchuks have been posting a daily puzzle that promotes Ukrainian culture (like the “spot the difference” from St. Sophia’s Cathedral at the top of this story) in hopes of raising money for aid. humanitarian and military.

Below are six puzzles that I selected from the family archives. If you enjoy them, consider contributing to their suggested causes. Slava Ukraine!

1. Hex vex

Which digit should replace the question mark?

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics

2. Ring ding

Which ring system differs from the others?

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics

3. Shake the snake

Which view of the 11-cube snake is incorrect?

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics

4. Fox box

Put a number in each box so that the 8 equations, across and below, are all correct. A box already has a number.

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics
This puzzle was created in collaboration with Harry Nelson

5. Sign mine

Which of the signs in the bottom row should replace the question mark?

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics

6. Elementary

For each of these six elements, find another element that has no letters in common with its counterpart. Each answer is unique.

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics
Created in collaboration with Donald Knuth

Hint: all the answers are known elements, words that are part of the vocabulary of a non-chemist.

NO SPOILERS. I’ll be back at 5pm in the UK with the answers.

Grabarchuk’s story began five decades ago when Serhiy, now 64, was a schoolboy in Uzhgorod. He discovered a talent for doing puzzles and magic tricks, and made a career out of it. In the 1990s he and his wife Tanya had a small business publishing puzzle books, and now the business has expanded to websites and apps and involves his sons, Serhiy Jr and Peter, and their wives, Kate. and Helen. The most successful puzzle in the family is Strimko, a Sudoku-style paper-and-pencil puzzle.

Can you solve it?  The magnificent Grabarchuks, the family of puzzles from Ukraine |  Mathematics
The Grabarchuk family Photograph: The Grabarchuk family

If you enjoyed today’s puzzles, consider donating to Ukraine. Here are links to National Bank of Ukraine donation pages for humanitarian and military support.

The Grabarchuks are on Facebook, Instagram and here is their website. Their most recent books are the Age of Puzzles series. All images in this story are their copyright.

I install a puzzle here every two weeks on a Monday. I’m always on the lookout for great puzzles. If you want to suggest one, write to me.

I’ve authored several puzzle books, including the most recent Language Lover’s Puzzle Book. I also give school lectures on math and puzzles (online and in person). If your school is interested, please contact us.

On Thursday, April 21, I will be giving a jigsaw workshop for the Guardian Masterclasses. You can register here.



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