Author: Colin

Dear Uncle Colin, I’m trying to work out $0.03 \div 0.1$. The answer is apparently 0.3, but I don’t understand why a division would make something bigger! Division Isn’t Very Intuitive, Decimals Especially Hi, DIVIDE, and thanks for your message! There are several ways to tackle this. I’ll start with

Dictionary of Mathematical Eponymy: The Sieve of Sundaram

I am not a number theorist. I mean… well scratch that. I am not an especially knowledgeable number theorist1 but I do enjoy number theory when it’s around my level. The Sieve of Sundaram is about my level. What is the Sieve of Sundaram? OK, let’s start with the Sieve

Ask Uncle Colin: The Area Between Two Curves

Dear Uncle Colin, I need to find the area between the graphs of $y=\sin(2x)$ and $y=\cos^2(x)$ in the interval $0 \le x \lt 2\pi$. I’ve found four solutions, but I think that means I need to do five separate integrals! Is there an easier way? Trigonometric Expressions: Double Integration Of

On Common Factors and Multiples

The marvellous @solvemymaths tweeted some time ago about finding least common multiples and highest common factors: I know the Venn diagram method for finding the Lowest Common Multiple is supposed to make it easier, but in my brain it just makes you do more maths. Also circumvents understanding if you're

Wrong, but Useful: Episode 80/80

In this, the final episode of WBU, @reflectivemaths and I discuss: @samuel_hansen's antiracism post((get well soon, Samuel)). Dave and I both assert that Black Lives Matter and acknowledge that we have a significant amount of work to do to create a just society. In a whiplash-inducing change of tone, tooth

Ask Uncle Colin: A Fraction of a Square

Dear Uncle Colin, I have been presented with this diagram: the marked points are a third of the way along the sides. I need to know what fraction of the grey square is shaded blue. Any ideas? Somehow Hued Area Defies Evaluation Hi, SHADE, and thanks for your message! There

A Sudoku Surprise

Once upon a time, I was a sudoku fiend. They provided an outlet, a distraction, a hiding place – I could bury my head in one for, say, half an hour and whatever had been troubling me before was somehow less of an issue. It’s not an effective strategy for

Ask Uncle Colin: An Octahedral Angle

Dear Uncle Colin, I have an octahedron, and I’m not afraid to use it! But I am afraid to find the angle between two adjacent faces. How would you do that? Protractors Lack Accuracy Tackling Octahedron Hi, PLATO, and thanks for your message! An octahedron is a shape made from

Resolving an Unfinished League

Last week, the English Football League season was cancelled, with standings decided on a points-per-game basis in League One and League Two1 In League One, that led to Wycombe Wanderers leaping into the playoffs at the expense of Peterborough, who had accrued the same number of points but played a

There is no Ask Uncle Colin today #strike4blacklives

In support of #strike4blacklives, there is no Ask Uncle Colin today. Please see Shut Down STEM to learn more. I will be spending the time I would have spend working reading Superior by Angela Saini in an attempt to fill some of the gaps in my knowledge. Black lives matter.