January 2025

Why Clocks Use ‘IIII’ Instead of ‘IV’

You may have noticed that old Rolex and other conventional watches write four as “IIII” instead of “IV” on the face. A curious quirk that has perplexed many watch enthusiasts. Actually, this design choice is neither arbitrary nor a mistake. Here’s why Rolex, along with many other clocks, opts for “IIII” instead of “IV.”

Historically, the use of “IIII” instead of “IV” on clock faces dates back to early clock making. In ancient times, “IIII” was easier to carve and cast than “IV”, making it a more practical choice. Over time, this practice became standard, particularly in sundials and mechanical clocks, where symmetry and uniformity were key.

From a mathematical perspective, “IIII” ensures symmetry on the dial. When you look at a clock face, the numerals must be evenly distributed. Using four “I”s instead of “IV” helps maintain a balanced visual structure, especially when compared to the “VIII” on the opposite side. This symmetry is crucial in maintaining proportionality, a key principle in both design and geometry.

rolex clock on street

Rolex, with its commitment to precision and timeless design, continues this historical tradition. The choice of “IIII” over “IV” reflects not just an aesthetic preference, but a mathematical balance and functional clarity, ensuring each dial is as legible as it is elegant.

Happy Learning!

The Missing Dollar Riddle

The well-known “Missing Dollar” puzzle! It’s fun because it smartly tricks our minds. Let us take it one step at a time:

The Riddle:

Three friends go out for lunch and spend $30. Each person contributes $10, so they pay $30 in total. The waiter realizes that the bill was only $25, so he gives back $5 to the friends.

Since $5 is hard to split evenly among three people, the friends decide to tip the waiter $2 and split the remaining $3, taking $1 each. Now, each friend has effectively paid $9 ($10 initially paid minus $1 returned).

Here comes the mystery:

  • Each friend paid $9.
  • $9 × 3 = $27.
  • Add the $2 tip, and you get $29.

But the friends started with $30. Where did the missing dollar go?


Breaking it down:

The riddle plays a clever trick on our logic by misdirecting the calculation. Let’s analyze the scenario step by step.

Step 1: The total money paid

The friends originally paid $30. Out of this:

  • $25 went to pay the bill.
  • $2 went as a tip.
  • $3 was returned to the friends ($1 each).

This accounts for the entire $30:

Step 2: Where the $27 comes from?

When we say that each friend paid $9, we’re effectively combining:

  • The $25 bill, which is part of what they paid.
  • The $2 tip, which is also part of what they paid.

So, the $27 already includes the tip:

Step 3: The trick

The riddle’s trick lies in the misdirection. It incorrectly adds the $2 tip to the $27 (the total paid) instead of properly accounting for where the money went. The tip is already part of the $27! There’s no missing dollar — it’s all accounted for.

The Conclusion:

The “missing dollar” doesn’t exist. The confusion arises because the riddle mixes two separate concepts: the total amount spent ($27, including the tip) and the original $30 contributed. By carefully tracing where each dollar goes, we see that the money is accounted for perfectly.

Why this riddle is so fun?

The Missing Dollar Riddle is a great example of how math can trick us when we’re not careful. It reminds us to always pay attention to what is being added or subtracted and why. It’s not just about numbers—it’s about logic and clarity.

Do you know someone who’d enjoy solving this riddle? Share it with them and see if they can figure it out before reading the explanation!

Happy riddling!

January 21 – Planetary parade

A planetary alignment is a spectacular celestial phenomenon in which planets appear to line up in the sky from our vantage point on Earth. Although the planets are still far away in space, their locations provide a visible alignment that fascinates stargazers and astronomers.

Today’s Planetary Alignment (January 21, 2025)

Tonight, six planets—Venus, Mars, Jupiter, Saturn, Uranus, and Neptune—will align in the night sky.

Visible Planets

Naked Eye: Venus, Mars, Jupiter, Saturn.

With Telescope/Binoculars: Uranus and Neptune.

Best Viewing Time

Shortly after sunset until around 9:30 PM.

Location and Tips

Look towards the western sky.

Choose a dark, clear location with minimal light pollution.

Happy Stargazing!