Living Museum of Learning

Where real moments become exhibits
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Are You Sure?

Are You Sure?

How TJ discovered % instead of being taught it

In TJ's class, Donald taught her int(input()) and let her experiment with the familiar arithmetic operators +, -, *, and /.

Then he gave her two more operators to investigate.

Nobody had taught her what // or % meant.

When TJ encountered %, her first thought was naturally:

“Percent?”

Donald laughed and explained that % had nothing to do with 100 or “percent”—just as * had nothing to do with the stars in the sky. They were simply operators.

He gave her only one hint:

The % operator has something to do with division.

TJ experimented.

After several attempts, she proposed her own explanation:

“It seems that I got remainders.”

Donald did not confirm it.

Instead, he asked:

“Are you sure? Is there any case you tried which failed to be a remainder?”

Now TJ had to do something deeper than recognize a definition.

She had to test a hypothesis.

Later, TJ received a simple homework problem:

Given an integer, print “even” if it is even and “odd” if it is odd.

Only about half an hour after class, she submitted:

n = int(input("n: "))
x = n % 2

if x == 0:
print("even")
else:
print("odd")

The solution was perfectly done.

Correct logic.

Correct use of %.

No missing pieces.

No unnecessary additions.

And even the spacing was clean and precise.

The operator she had not been taught had become a tool she could independently use.

The most powerful learning sometimes begins with not being given the answer.

TJ first observed the behavior of an unfamiliar operator.

She formed a hypothesis.

She searched for evidence.

She considered whether her explanation could fail.

Then she applied the discovered idea to a new problem.

In less than an hour, the path was:

unknown → experiment → hypothesis → verification → application → mastery

The final homework looked simple.

The thinking behind it wasn't.

A student can discover the meaning of an unfamiliar programming operator without first being given its definition.

Let the student experiment, offer a small hint, and replace “Yes, that's right” with the more powerful question: “Are you sure?”

When students discover and verify an idea themselves, they don't merely remember the rule. They begin to trust their own ability to figure things out.