Blog Post #3: Gifts For All

Dear Readers,

Given that 3 is my favourite number nowadays, and this is my third blog post, I will begin with a powerful quote of 3×3-3÷3 words. “God’s gifts put man’s best dreams to shame” comes from Elizabeth Barrett Browning (famous English poet, 1806-1861), and can help us all to value what is most important. When I was a child, I might have been expecting only two words, but I’m thankful that my parents and teachers taught me more, especially about the content. Proverbs 22:6 also provides a great reminder to “Start children off on the way they should go, and even when they are old they will not turn from it.”

The simple picture below was a favourite of mine on the door of the main classroom where I worked, because it was a personal gift, thoughtfully made.

Here come three fun challenge puzzles based on the picture.

All The Threes

If you add up all the threes in picture, is the total more or less than the total number of letters in ST. JOHN’S INTERNATIONAL SCHOOL?

 

Zero The Hero

Mentally calculate 3333333×3-3. What is missing from 3333333×3-3 if we want the result to equal zero?

The next puzzle is something to really get your teeth into…!

Threes Mental Multiplication Brainteaser

  1. Mentally calculate 3x3x3x3.
  2. Think of 8×8, and then write down the answer to 80×80.
  3. Now mentally figure out 81×80.
  4. Go a step further and mentally figure out 81×81.
  5. Now state the answer to 3x3x3x3x3x3x3x3.
  6. Finally, mentally calculate 3x3x3x3x3x3x3x3x3.

Chess Brainteaser: Mate in 3+3÷3 moves!

  1. On which day of the week, and at what time, did Mr. Mo compose this chess brainteaser?
  2. If it’s Black to move, how can he force checkmate in at most 3+3÷3 moves?

SOLUTIONS

All The Threes

In the “threes” picture given before, the total of the nine threes is 27, which is 1 more than the total number of letters in ST. JOHN’S INTERNATIONAL SCHOOL.

Zero The Hero

3333333×3-3=9999999-3, which equals 9999996.

However, 3333333x(3-3)=3333333×0, which equals zero.

Threes Mental Multiplication Brainteaser

  1. 3x3x3x3=(3×3)x(3×3)=9×9=81.
  2. 8×8=64, and so 80×80=6400.
  3. 81×80=80×80+another 80, and that makes 6400+80 which gives 6480.
  4. 81×81=80×81+another 81, and that makes 6480+81 which gives 6561.
  5. 3x3x3x3x3x3x3x3=(3x3x3x3)x(3x3x3x3)=81×81=6561.
  6. 3x3x3x3x3x3x3x3x3=3x(3x3x3x3x3x3x3x3)=3×6561=(3×6000)+(3×500)+(3×60)+(3×1)=18000+1500+180+3. The total is 19683.

Chess Brainteaser: Mate in 3+3÷3 moves!

  1. As you can assume from the bottom left-hand area of the picture, Mr. Mo composed this chess brainteaser on a Saturday at 17:01 (local time).
  2. Black forces checkmate in at most 4 moves with 1…g5+ 2 Ke3 (or 2 Kxe4 Qe2#) 2…Rd3+ 3 Kf2 (or 3 Kxe4 Qe2#) 3…Qxh2+ 4 Ke1 Qd2#. 3…Rd2+ is equally effective.

Chess Joke

Some friends find Mr. Mo playing chess against a baby. They are astonished and say: “What a clever little kid!”

“No, no, he isn’t that smart! I’m leading by four games to one!”

 

Author: Paul A. Motwani

My name is Paul Motwani, but my colleagues, my students and their parents mostly call me "Mr. Mo"! My middle initial, A, stands for Anthony, because I was born on the official feast day of St. Anthony of Padua, the patron saint of miracles and of lost souls. I love teaching Mathematics and Chess, and giving fun-packed talks and shows in schools and clubs. The popular ingredients of Math, Chess, Mystery and Magic are my "Fantastic Four", and I give prizes too! I am an International Chess Grandmaster, and (loooooong ago!) I was the World Under-17 Champion. I am the author of five published chess books and hundreds of newspaper articles. I live with my wonderful wife and son in Belgium. I also love music, movies and puzzles. I blog at paulmotwani.com. My e-mail address is pmotwani141@gmail.com. You can find me on Facebook, too.

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