Today is September 13, 2019, Friday. You must have read in my earlier blog about ‘Triskaidekaphobia’ the fear of number 13 (from Greek tris (‘three’), kai (‘and’), and deka (‘ten’), and ‘Paraskevidekatriaphobia’ is the term used to describe the fear of ‘Friday the thirteenth’ – (Greek words paraskevi (‘Friday’) and dekatria (‘thirteen’) with –phobia as a suffix to indicate ‘fear’).
There is another astronomical significance for this Friday the 13th – it coincided with Full Moon. Last time a full moon appeared on Friday the 13th was in October of 2000. This Full Moon is also called a ‘micro-moon’ because it is at its farthest point from Earth – also known as its apogee. Being at the farthest point, the moon appeared around 14% smaller than usual and much dimmer than a normal Full Moon.
As this Full Moon fell immediately before Fall Equinox, It is called a Harvest Moon.
The term ‘Equinox’ comes from Latin meaning ‘equality of night and day.’ It occurs twice in a year – one in Spring (22 March) and one in Fall (22 September), that is when the Sun crosses the celestial equator, causing day and night to be of 12 hours each. In Canada, Fall Equinox marks the beginning of Fall season.
‘Harvest Moon’ is an old European term applied to a full moon that rises closest to the beginning of fall. In the earlier days when the farmers could not illuminate their farmland, the bright light of the moon facilitated farmers to work a little later into the night to bring in their crops well before Fall set in.
As if to facilitate harvest, the harvest moon rises 10 to 30 minutes after the sun sets, whereas most moons rise approximately 50 minutes after sunset. In Toronto, on September 13, the sun did set at 7:31 PM and the moon rose at 7:46 PM. This time gap between sunset and moon-rise was even shorter as one moved closer to the North Pole.
The next Full Moon on a Friday the 13th will appear in August 2049.
When our son Nikhil was in Grade 3, he encountered his first mathematical roadblock: division. Along with it came the twin challenges of prime numbers and factors – concepts that can confound young minds. Rather than resort to worksheets and drills, we decided to make arithmetic come alive through a game that transformed everyday commutes into learning adventures.
Nikhil and I spent nearly half an hour together in the car each day – driving to school, picking him up, ferrying him to swimming practice, tennis lessons, or music class. He affectionately called this our father-son time, using it to discuss topics he thought might attract teasing from his mother or sister. This tradition continues to this day, the subjects evolving as Nikhil progressed from Grade 3 to Grade 12.
Drawing from Memory
I reached back into my own school days, specifically to lessons from Mr. Venkitesha Murthy, our Grade 7 mathematics teacher. Mr. Murthy possessed a rare gift: he taught mathematics through stories, anecdotes, and riddles. He inspired us with tales of Indian mathematical giants – Ramanujan, Bhaskara, and Aryabhatta. Even in Grade 7, I had struggled to grasp factors and prime numbers, so Nikhil’s difficulty came as no surprise. What mattered was finding the right approach.
The Licence Plate Game
In Ontario, most licence plates follow a pattern: four letters followed by three digits. Three-digit numbers proved perfectly manageable for a Grade 3 student. So we devised a simple game. Every vehicle we encountered on our drives became a mathematical puzzle to solve.
We would analyse each number systematically:
Is it even or odd? That determined divisibility by 2.
Add all the digits. If the sum was 3, 6, or 9, the number was divisible by 3.
For even numbers, if the last two digits were divisible by 4, then 4 was a factor.
If the last digit was 5 or 0, the number was divisible by 5.
If both 2 and 3 were factors, then 6 automatically became a factor.
If the sum of digits was 9, the number was divisible by 9.
If the last digit was 0, then 10 was a factor.
Each day, we analysed about ten licence plates. Within weeks, the mysteries of division, factors, and prime numbers had largely dissolved.
A Licence Plate That Defined Me
Shortly after our arrival in Canada, my wife bought me a new Honda Accord. When I went to take delivery, the agency had already procured my licence plate: BBZW 139.
In North America, licence plates belong to the owner, not the vehicle. When you sell or change vehicles, you keep your plates and affix them to the new one. Thus, BBZW 139 remained with me through three car changes.
The number 139 intrigued me. It is odd. It is prime – divisible only by 1 and itself. I came to see it as a reflection of my personality: unable to be affected by external factors, undivided by anything other than the Almighty and myself.
The Curious Case of 13
The digits of 139 add up to 13 – my birth date (13 March). My school roll number was 931, which also summed to 13. My Defence Account Number was 161005, adding once again to 13. The coincidences multiplied.
I do not believe in numerology or astrology, so this trail of 13 has never cast its supposed bad luck upon me. Nor has it brought exceptional fortune. It simply is.
The Many Faces of Thirteen
The number 13 carries rich cultural associations:
Baker’s Dozen: In thirteenth-century Britain, the Assize of Bread and Ale regulated the relationship between wheat prices and loaf sizes. Bakers who inadvertently shortchanged customers faced severe penalties. To protect themselves, they began counting 13 as a dozen – the famous “baker’s dozen.”
Coming of Age: Children become teenagers at 13 – a transformation we all understand.
Apollo 13: The only unsuccessful moon mission, yet its astronauts returned safely despite an oxygen tank explosion that left their survival hanging in the balance for days.
The Last Supper: Many Christians associate 13 with bad luck because 13 people were present at the Last Supper.
The Fear of Thirteen
Triskaidekaphobia—from the Greek tris (three), kai (and), and deka (ten)—is the fear of the number 13. Paraskevidekatriaphobia specifically denotes fear of Friday the 13th, combining paraskevi (Friday) and dekatria (thirteen) with the suffix -phobia for fear.
Researchers estimate that at least 10 percent of the US population harbours some fear of the number 13, particularly when it falls on a Friday.
Why 13 Gets a Bad Rap
Mathematicians offer a more rational perspective: 13 is not inherently unlucky. It suffers from following the perfect number 12. Twelve offers a dozen, twelve months in a year, two twelve-hour cycles in a day. The perfection of 12 casts an undeserved shadow on its successor.
Yet Triskaidekaphobia’s influence in America is so pronounced that over 80 percent of high-rise buildings lack a 13th floor. Hotels, hospitals, and airports routinely avoid using the number for rooms and gates.
A Final Reflection
The number 13 may be considered lucky or unlucky depending on cultural context, but one cannot blame the number itself. It simply follows 12 and precedes 14, fulfilling its mathematical destiny without malice or favour.
Postscript
I no longer possess the BBZW 139 licence plate. The Government of Ontario, Canada, in recognition of my service with the Indian Army, has honoured me with a new Veteran Plate. My gratitude to Canada for extending this recognition to a veteran from another country knows no bounds.
But I will always remember the game that taught my son division – and the prime number that came to define me.
REJINCES 