If Math were the only subject we take, remembering all formulas would be possible.
But it’s not.
You also learn how rocks form in Geography, how acid and alkali interact in Chemistry, how Hitler orchestrated the deaths of millions in History, etc.
So it’s a little tricky.
Truth is, not all Math formulas need to be formulas.
And if they are not formulas, you don’t have to remember them.
Take polygons for example.
If you need to find the internal angles of a pentagon and you can’t find the formula in your memory. What can you do besides giving up?
You can draw the pentagon.
But wait. What if you also forgot how many sides a pentagon has? Well, some of us dream of owning a penthouse. A kindergarten drawing of a house looks like this.
Pentagons have 5 sides.
And since we’re on this topic… Hexagon has an x which the number six has, so it has 6 sides. Octagon has 8 sides, we all know. Nanogon has 9 sides because it spells like nine. Decagon has 10 sides because a decade has 10 years. Then the last one — the heptagon — has 7 sides of course.
I digress. We were looking for the internal angles of a pentagon.
Now you have a drawing of a pentagon (or an ugly house), you can mark out triangles.
A pentagon has 3 triangles if you draw lines from end to end. So all internal angles add up to 180º (angles in a triangle) x 3 = 540º.
Each internal angle will then be 540/5 angles = 108º.
This might sound worse than remembering a formula. But once you know this trick, it stays in your brain for life.
Second example — how do you find the circular surface area of a cylinder?
Take a piece of paper, and roll it up from end to end. It becomes a cylinder!
The circular surface area of a cylinder is therefore the length x breadth of the piece of paper. The breadth is the circumference of a circle, pi x d.
Read this story about Cally to visualise this.
There are lots more and if you have any, share them with me at hello@mathcally.com 🙂