Is the Numbers & Math lesson free?

Yes. The first 5 lessons on PyRun are free forever — no signup, no card. Numbers & Math runs real Python in your browser via Pyodide.

How long does the Numbers & Math lesson take?

About 5 minutes end-to-end. It's a hands-on lesson — you read a paragraph, edit the code, and run it in the same tab.

Do I need to install Python to try the Numbers & Math lesson?

No install required. PyRun runs real CPython in your browser via Pyodide (Python compiled to WebAssembly). Works on Chrome, Firefox, Safari, and Edge — desktop or mobile.

What level is the Numbers & Math lesson?

Beginner level. No prior Python required — good starting point.

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Beginner·5 min·basics · math

Numbers & Math

You’ll be able to

Perform integer, float, and modulo arithmetic accurately
Choose between / (float division) and // (floor division)
Use math module functions like sqrt, log, pow
Round and format numbers with round() and f-string precision

Why this matters

Float arithmetic quirks like 0.1 + 0.2 != 0.3 cause real production bugs in billing, trading, and analytics code. Libraries like decimal and numpy exist precisely because devs kept losing rupees to floating-point drift.

Common pitfalls

Using / when you meant //. Integer division matters for indexing; len(x)/2 gives a float and breaks slicing.
Forgetting operator precedence: 2 ** 3 ** 2 is 512, not 64, because ** is right-associative.
Comparing floats with ==. Use math.isclose(a, b) for anything derived from arithmetic.

Python handles integers and floats natively. The math module adds the rest.

Operators worth remembering

+ - * / — the usual
// — floor division (drops the remainder)
% — modulo (the remainder)
** — exponent

Built-ins

abs(), round(), min(), max(), sum([...]).

Try it

Compute compound interest: 1000 * (1.07 ** 10).
Use math.log(1024, 2) — guess the answer first.

Practice

3 graded exercises

Write the code, click Check. We’ll tell you exactly what to fix.

Progress0 / 3

Exercise 1
Print the integer (floor) division of 100 by 7. Output should be exactly 14.
Exercise 2
Print 2 raised to the power of 8. Output should be exactly 256.
Exercise 3
Import math and print π (pi) rounded to 3 decimal places. Output should be exactly 3.142.

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Numbers & Math

You’ll be able to

Perform integer, float, and modulo arithmetic accurately
Choose between / (float division) and // (floor division)
Use math module functions like sqrt, log, pow
Round and format numbers with round() and f-string precision

Why this matters

Common pitfalls

Using / when you meant //. Integer division matters for indexing; len(x)/2 gives a float and breaks slicing.
Forgetting operator precedence: 2 ** 3 ** 2 is 512, not 64, because ** is right-associative.
Comparing floats with ==. Use math.isclose(a, b) for anything derived from arithmetic.

Python handles integers and floats natively. The math module adds the rest.

Operators worth remembering

+ - * / — the usual
// — floor division (drops the remainder)
% — modulo (the remainder)
** — exponent

Built-ins

abs(), round(), min(), max(), sum([...]).

Try it

Compute compound interest: 1000 * (1.07 ** 10).
Use math.log(1024, 2) — guess the answer first.

Practice

3 graded exercises

Write the code, click Check. We’ll tell you exactly what to fix.

Progress0 / 3

Exercise 1
Print the integer (floor) division of 100 by 7. Output should be exactly 14.
Exercise 2
Print 2 raised to the power of 8. Output should be exactly 256.
Exercise 3
Import math and print π (pi) rounded to 3 decimal places. Output should be exactly 3.142.