Probability questions about choosing at random are easy to describe in English, but frustratingly difficult to compute. I design and build a new calculator to make it easier to ask and answer these probability problems.

Solving an expected value problem by multiplying polynomials. Also, I ask (and fail to answer) a seemingly difficult question about limits.

How manually manipulating strides opens up new array operations, and why swapping tiles of 2D arrays requires *four* dimensions.

Exploring how manipulating stride lengths can transpose an array, as well as C vs. Fortran contiguity.

A detailed look at strides are used to define the shape and order of multi-dimensional arrays.

Implementing expressions to approximate $\pi$ using J and the power of hooks.

Presenting the slow, faster and (possibly) fastest algorithms to count permutations that avoid repeating letters.

What makes this algorithm work? A simple overview of the key steps and code involved.

Jumping through hoops to write the famous Quake 3 code in Python.

Well, not quite 100 yet. You can find them at github.com/ajcr/100-pandas-puzzles

Where did the value of 0.145 come from? Contour plots.

There are two strategies to accumulating reputation, answer fast, or answer slow. Here's how to go slow and build upvotes.

Is there a neat way to turn a list into a tower of powers?

einsum is one of NumPy's jewels. What does it do?

I argue it's mostly blue and green.

Exploring domain names to find the words nobody has used yet.

Hello and welcome.