Blog Post #171: A Noble Arc ❤️

Dear Readers,

Welcoming archways in Heaven will be infinitely more beautiful than anything we can imagine or have seen so far.

Every time that someone is saved is a reason for great celebration in Heaven.
None of us need miss out on the everlasting joy of God’s Kingdom.
We are all warmly invited. ❤️
Will you accept?

Why not decide to happily answer “YES” in your heart right now (if you haven’t yet done so)? ❤️

I also gratefully thank God for giving the beautiful ideas for all the puzzles and brainteasers in this (and indeed every) blog post. You are always very welcome to send me by email your answers to some or all of the goodies, if you would like to do so 👍❤️

The Loving Living Spirit Equation 💕

L + S + L * S = L2 + S2 + 1

The above equation is my absolute favourite one ❤️

Given that God’s Love and Spirit are real and are represented here by L and S, my favourite brainteaser for you is to solve (with proof) the equation

L + S + L * S = L2 + S2 + 1

Puzzle to Celebrate a Lovely Couple 💕

Here in Blog Post #171, think of the largest prime divisor (or factor) of 171. The correct prime factor (19) is the number of years that Patrick & Roberta have been married, and they’re planning a wonderful summer feast later this year to celebrate their 20th wedding anniversary 💕

Roberta & Patrick will soon be celebrating their ‘China’ wedding anniversary = 20 years 💕

Suppose that P, R & I represent three different prime numbers, and I + R = P. Also, R + R – I = 20.

To discover the day number and month when my wife (Jenny) and I are going to celebrate with Patrick & Roberta, figure out the exact value of P * R * I * I ÷ 20.

Puzzles in Honour of Students 👍😊

Imagine a mathematical student saying to me, “Mr. Mo, I’m thinking of a particular year _ _ _ _ from within the time of your life so far. If I insert my favourite one-digit number in the middle, to get _ _ _ _ _ , then the resulting number equals the cube of my house number !”

Your fun challenge is to figure out both the student’s favourite one-digit number and the house number 😁.

Warm Welcome to Anna K. Puzzle 😍

Anna K. is the newest student who arrived at Musica Mundi School (MMS) just a few days ago. It’s lovely that she’s featuring here in Blog Post #171, because Anna’s birthday is actually 20 June = day number 171 of the year! This year, she’ll be turning from 16 to 17.

(16 + 17) * FUN = 20FUN

where FUN represents a certain three-digit number and 20FUN represents a five-digit number.

Your FUN puzzle is to figure out the exact value of FUN.

B😊NUS PUZZLE

I’m now thinking of three particular, consecutive prime numbers. The total sum of their squares equals 3171.

Your fun bonus challenge is to figure out exactly which three prime numbers I’m thinking of.

Happy Valentin’s Day Puzzle!! 😁

Today, 25.1.25, is the 25th day of the year, and also the birthday of Valentin, one of my Mathematics students at MMS. In HH days from now (where HH represents a particular two-digit number), it will be day number XY of this year, where XY represents a rather special two-digit number. A delightful detail is the fact that XY days is actually equal to X days + Y weeks 😊

Your fun puzzle challenge is to figure out the exact values of H, X and Y.

A FAV Puzzle 😍 (in honour of students Faye and Artemii (& Valentin of course) whose birthdays are coming up within the next couple of days).

Faye, Artemii and Valentin know that 3 is my absolute favourite number, but I also like square numbers. So, imagine that they discover the smallest positive whole number W for which W squared begins with three 3s (on the left).

The fresh fun challenge is to discover the exact value of W 👌😊.

A Circular Cakes & Cream Brainteaser 👌😍

I couldn’t help imagining delicious cakes and cream when looking at the diagram of 4 identical circles set up nicely on a square tray 😁!

Your tasty brainteaser is to figure out (correct to 4 significant figures) the area of the central yellow part as a percentage of the area of the entire square.

Extra-special congratulations if you can prove mathematically that your answers up to here in this blog post are the correct solutions to the two brainteasers and six number puzzles presented so far.

A Knight’s Tale about King Richard! 🤣😂

A very nice photo from last October.
Richard is one of the keenest students who loves to play at the Musica Mundi School Chess Club😊.

Last week, just for fun, Richard sneakily moved a queen like a knight in order to turn a ‘checkmate in two moves’ puzzle into an immediate mate in one move!! Everyone there (myself included) had a good laugh about it!

Now, though, I’m making sure to present a puzzle position involving a real knight but no queen! 😂

It’s a delightful puzzle that I saw posted recently on Facebook.

It’s White to play and force checkmate in not more than six moves! 😍

Word Puzzle: Rearrange the letters of A NOBLE ARC to make the name of a very well-known, stunning city beginning with B.

I may visit beautiful Barcelona some day…
but Heaven is where I want to live forever
and it’s free for everyone who recognises
and gratefully accepts God’s gift.❤️

Let’s enjoy an extra double bonus brainteaser treat before wrapping up this blog post!! 🙌😊

Two friends share the same birthday (25 January), but their ages are several years apart. Today, the younger friend said to the older one: “When I reach the age that you are now, the product of our ages then will be very nearly 200 more than the product of our ages now.”

This modest brainteaser/puzzle is for you to figure out (with proof) the exact dates of birth of the two friends.

In a particular family, the father is several years older than his wife. Let’s call their age difference N. They also have N children. One great grandfather is still alive, and he helps to make Maths homework easier for everyone! 👍😁

The product that would result from multiplying together N by the ages of the great grandfather, the father, and his wife, would of course be a large number, but curiously it would only involve one particular digit repeated all the way from the start, left-end of the number to the finish, right-end of the number.

Your Brainteaser Challenge is to figure out the value of N, and also the ages of the great grandfather, the father, and his wife.

To finish, here is a beautiful quote from John 17:1 in The Bible:

After Jesus had spoken these words, He looked up to Heaven and said, ‘Father, the hour has come; glorify your Son so that the Son may glorify You.’

Blog Post #170: Now Is The Time; Best Groningen Chess 👍😊❤️

Dear Readers,

Let’s begin with a quick, wee warm-up of three checkmate puzzles in 3, 3 or 3+3 moves based on a trio of actual games from…1925 ! 😁

Checkmate Puzzle Solutions

A) 1 Qf7+! Kxf5 2 g4+ Kxg4 3 Qh5#

B) 1 Rxe6! leaves Black with nothing better than 1…Rff7 2 Bxg7+! Rxg7 3 Re8#

C) 1 Rxh7+! Kxh7 2 Qh3+ Kg6 3 Qh6+ Kf5 4 Qh7+! Kg4 5 Qh3# or 4…Rg6 5 Qh3+ Ke4 6 Nc3#

The multiple purposes of this article include:- most sincerely wishing everyone a very blessed, happy New Year; writing about a wonderfully-organised international Chess festival which concluded on December 30 in Groningen in the North of The Netherlands; sharing some good fun freshly-created puzzles (involving Chess, Mathematics and more); sharing a vitally-important reflection which I honestly know more about, with certainty, than anything else I know. Indeed, it’s the duty of everyone who knows the Good News to share it with others, in the hope that they will come to love, respect and accept with gratitude to God the priceless gift which He offers freely to everyone. Peoples’ individual decisions to accept the gift (or not) will be of eternal importance, so it’s not something to ignore or delay.

❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

A lovely Chess for Peace 💕 card given to me previously by Erik van de Wynkele

Since the age of 11, I have enjoyed taking part in nice Chess events during some of my ‘free’ time. Currently, I play competitive Chess only during school holidays, because throughout term times I dedicate a lot of time and energy to giving the highest quality of Mathematics teaching that I can for all of my students. Also, time with family and time to rest well is always important.

I am grateful to Mr. Govert Pellikaan and his fantastic team of organisers & arbiters who made the splendid Groningen Chess Festival run really smoothly for the enjoyment of around 400 people who took part. Meeting so many friendly people was a great pleasure.

Mr. Govert Pellikaan
Photos by Harry Gielen. Pictured above is the team of arbiters.

Many participants chose for one of the 9-round Open sections, while some others opted for a 4-player, 3-round, all-play-all mini-group. Yet others (including myself) were more than happy with the possibility of playing in a compact 5-round event starting on Boxing Day (26 December). Whichever event one chooses for, it’s highly appealing that its schedule requires just one game per day.

Everyone plays together in a lovely, spacious hall. Drinks, snacks and meals are readily available within the analysis room of the same building, at good prices.

A superb Chess bookstall is provided by Robert Klomp and his wife, WGM Erika Sziva, whose website is http://www.debestezet.nl 👍❤️ The thriving business was founded in 1994.

I was delighted to win the Senior Tournament with 5/5, and the next day my wife (Jenny) and I celebrated New Year’s Eve at the home of Robert & Erika in the Dutch town of Best, where we stayed until the evening of New Year’s Day—a favourite, long-standing tradition with our families 😊😊

A typically stunning photo 😍 by Erika, who is extremely talented.

Robert & Erika having fun! 😁
We all tried to remain well-balanced!! 🤣😂
Jenny & I celebrating the New Year in The Netherlands 💕
We named this photo ‘Orange Peace’ 😊
Orange is a national colour in The Netherlands.
Imagine a great Chess board with its unit squares numbered from 1 to 64.
Jenny and I have gone a long way to reach number 63, with some special thoughts in mind…
for bringing you six threes with a sneaky, fun twist!
Think of the year 1925, from a century ago. Reverse its digits to get 5291.
Multiply by 63, and the result is a super six-digit string 333333
consisting entirely of 3s; my absolute favourite! 😁

Question: How can you use the numbers 100, 64, 3 and my house-number 11 to get 21.12, to remind you of December 21, the date when the annual Groningen Chess Festival begins?

Answer: 64 x 3 x 11 ÷ 100 = 21.12 👍😁

Word Puzzle: Can you read my mind and rearrange the 18 letters of CONGRESS BEGINS THEN to make 3 other very particular words!?

Photo by Bart Beijer

Answer: I was thinking of

CONGRESS BEGINS THEN =

BEST GRONINGEN CHESS 👍😊❤️

Nice Number Puzzle: Why is today, 3.1.25, a nice day for me to gratefully celebrate a 5/5 result?

Me with International Master Vadim Cernov,
who was the runner-up on 4/5 in the Senior Tournament.

Answer: 5 to the power of 5 equals 3125 🙌😁

IM Arthur De Winter, WGM Machteld Van Foreest (who achieved an IM norm—warm congratulations! 👍😊), GM S.L.Naranyan, IM Theo Stijve, IM Anto Cristiano F Manish
and GM Thomas Beersden were 6 of the top 7 prizewinners in the Open A-Group.
IM Nick Maatman would also have been pictured, but he had had to leave, sick.

Given that 17-year-old Machteld Van Foreest is a local player from Groningen, her IM norm achievement was a particularly popular result. Today, I have been enjoying playing through some of Machteld’s earlier victories from 2024. I have chosen the following position from the Dutch League, in which it was Machteld as White to play and win by force…and she did so! 😁

The game ended crisply with 1 Re6! Qg5 2 f4! 1-0. Black resigned in view of 2…Qh4 3 Rh6#. It’s true that 1…Qh7 would have been more tenacious, but White would still have won comfortably with 2 Qf4!, intending 2…Rxd5 3 Rh6.

Literally hundreds of great photos were taken by Bart Beijer and Harry Gielen at the tournament. Though I can’t feature all of them here, I do want to congratulate most sincerely every person who was there in Groningen, for everyone’s presence contributed to making an unforgettable event 💕

It was especially nice for me to see Mr. Johan Zwanepol, who was the main organiser when I previously played in Groningen in 1979, 1980, 1989 and 1990 😊

Mr. Johan Zwanepol presenting the Open A-Group Winner’s Trophy to Indian GM S. L. Naranyan 👌😊❤️
13-year-old Scottish super-talent Rishi Vijayakumar very nearly achieved an IM norm.
He still deserves ’10/10′ for excellent, courageous play.
Rishi loves Maths, too. So, here comes a nice puzzle in his honour…

Without needing to use a calculator or any other external aids, can you figure out mentally the exact value of the square root of (1+3+5+…+2023+2025)?

The key secret is that the total sum of 1+3+5+…+the nth odd number

always equals n squared exactly. Since 2025 = 2 x 1013 – 1, we can know that 2025 is the 1013th odd number. So, 1+3+5+…+2023+2025 must equal exactly 1013 squared. Taking the square root leaves us with 1013 in honour of 13-year-old Rishi (to whom I awarded 10 points) 🙌😊

Chess Helpmate Puzzle

A delightful Chess puzzle which I saw posted on Facebook recently.

It’s Black to play and co-operate fully in a Helpmate in six moves! That is, Black starts a co-operative sequence which ends with White delivering checkmate on his 6th move. Can you do as well as Problem-Solving Chess Grandmaster Dolf Wissmann by cracking the puzzle in under a minute!? 👌

Solution:

Once we realise that the required end-position is this one, it becomes much easier to figure out that it can be reached from the puzzle’s starting position via the sequence
1…g5 2 Kf2 g4 3 Ke3 g3 4 Kd4 g2 5 Kxd5 g1=B 6 Kc6 Ba7 7 Kc7#

Bonus Two-Part Fantasy Chess Puzzle 💕

  1. What is the maximum number of rooks which can be placed on an empty Chess board such that none of them are attacking each other?
  2. What is the maximum number of knights which can be placed on an empty Chess board such that none of them are attacking each other?

Answers

  1. Eight rooks, placed on a common long diagonal of a Chess board, will not be attacking each other.
  2. 32 knights, either all on dark squares or all on light squares, will not be attacking each other.
Happy New Year Wishes from Paul, Jenny & Michael Motwani ❤️❤️❤️

A Happy New Year Trigonometry Puzzle In Honour of

Chief Arbiter Erwin Denissen, who is also a Mathematics Teacher

Photo by Bart Beijer of Erwin Denissen & Harry Gielen 👍👍

Without needing to use a calculator or any other external aids, figure out mentally the exact value of the square root of sin 2025° * cos 2025° * tan 2025°

Answer:

sin x° * cos x° * tan x° = sin x° * cos x° * (sin x° ÷ cos x°) = (sin x°) squared, and so its square root will be the absolute value of sin x°.

sin 2025° = sin (5 x 360 + 225)° = sin 225° = -sin 45° = -1/sqrt 2.

Its absolute value is 1/sqrt 2 or equivalently (sqrt 2) ÷ 2.

Another Sneaky Square Root Surprise!

Think about the square root of 2025. What surprise do we get if we increase each digit of 2025 by 1 and then take the square root?

Answer: The square root of 2025 is 45. The square root of 3136 is 56. Both digits in the answer increased by 1, too! 😁

I will round off this article with one final nice photo and a beautiful, true quotation.

“You pay God a compliment by asking great things of Him”—St. Teresa of Avila 💕