1. Planck Time.

10⁻⁴³ seconds: Planck time—smallest measurable unit. 

• Named after Max Planck, German theoretical physicist (1858–1947), the founder of Quantum Theory and Physics Nobel Prize winner 1918.

2. Negative 40 coincidence.

-40 °C equals -40 °F, the only point where Celsius and Fahrenheit meet

3.

1728 — The “Dozen Cube”.

12³ = 1728
That’s why:

• a gross = 144
• a great gross = 1728

Old trading systems were built around this cube.

What “gross” and “great gross” are

• Gross = 12 × 12 = 144

• Great gross = 12 × 12 × 12 = 1,728

They’re based on duodecimal (base-12) counting, not base-10.

When trading systems started using them

Antiquity → Medieval period

• Base-12 and base-60 counting came from Mesopotamia (c. 3000 BCE).

• By Roman and medieval Europe, trade commonly used:

  • dozens

  • scores

  • grosses

• This was especially common for physical goods:

  • nails, buttons, pens

  • cloth fasteners

  • candles

  • playing cards

  • early manufactured items

Why?

• 12 divides cleanly into halves, thirds, quarters, and sixths.

• This mattered in a world without calculators or standardized weights.

By 1200–1600 CE, gross and great gross were standard commercial quantities in Europe.

When they peaked

1400s–1700s (early capitalism)

This was their golden age:

• Guild systems priced goods by the gross

• Wholesale contracts often specified grosses

• Warehousing and shipping used them because they packed efficiently

• Accounting books routinely referenced them

At this stage, they weren’t “special numbers” — just practical ones.

When they began to decline

Late 1700s–mid-1800s

Several forces pushed them out:

1. Decimalization

• France introduced the metric system (1790s)

• Other nations followed slowly

• Base-10 math simplified taxation and accounting

2. Modern finance and abstraction

• Trading shifted from goods to prices, futures, and contracts

• Decimal currency (cents, pence) became dominant

• Ratios replaced unit-counts

3. Industrial standardization

• Factories preferred:

  • round base-10 quantities

  • standardized SKUs

  • uniform packaging

By 1850–1900, gross and great gross were no longer core trading units in financial systems.

Did trading systems ever “stop” using them?

Not completely.

They survived in niches:

• Hardware (screws, nails)

• Stationery (pens, pencils)

• Buttons, hooks, snaps

• Some wholesale packaging today still uses gross

But:

• Markets, exchanges, and financial trading systems stopped using them entirely.

• They don’t appear in modern price discovery, order books, or settlement systems.

Important clarification

Gross and great gross were counting units, not pricing ratios.

Modern trading systems moved toward:

• percentages

• ratios

• spreads

• statistical distributions

That’s why numbers like 1.618 (phi) show up conceptually, while 144 disappeared operationally.

Why this question is interesting

Gross (144) didn’t vanish because it was wrong — it vanished because trade stopped being about counting objects and became about abstract value flows.

Base-12 was better for hands and goods
Base-10 was better for ledgers and machines

4. Square numbers ending in 5.

For n5²: n × (n+1), then append “25”.

Example: 65² → 6 × 7 = 42, append 25 → 4225.

5.

Divisibility Rule for 6:

 A number is divisible by 6 if it’s divisible by both 2 and 3.