Purplemath
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Purplemath
@purplemath.com
93 followers 70 following 290 posts
Purplemath is a free algebra lessons website. The author, Elizabeth Stapel, always had trouble with math; her lessons show the methods that finally worked for her. Purplemath is where you go when the book and the instructor aren't making any sense.
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purplemath.com
After a certain age, yeah, this looks about right.

#Youtube #youtubetutorial #tutorial #tutorialvideo #influences #newskills #mathhumor #purplemath
The graphic is titled "Source of New skills". Below it are two horizontal bars, each having segments that denote the percentages that each listed component provides Bar 1: This bar gives the relevant percentages, and is titled "10 Years Ago". About 3/8 of the bar is yellow and is labeled "Parents"; the middle section is red,is about 1/8 of the bar, and is labeled "Life"; the final segment takes up the remaining 4/8, or 1/2, of the bar, is green, and is labeled "Education". Bar 2: This bar is labeled "Now". The odors for the inputs of "Parents", "Real Life", and "Education" are squeezed down to the left-hand end of the bar. The remaining 9/10 (?) of the bar is blue, and is labeled "YouTube tutorials".
December 11, 2025 at 3:56 AM
purplemath.com
#eccentric #eccentricity #professorlife #scientist #science #sartorial #SartorialStyle #mathhumor #purplemath
Kaijino says, "Also, being a scientist pretty much gives you a free pass to be as eccentric as you want. Like, you'll be at a conference and it's like 'Is that guy wearing socks and sandals and plaid pants???' 'Yah, but he was on the team that discovered gravitational waves; let him be.'" inthisquarter replies, "I once saw a highly respected minerologist take a slice of watermelon, put it between two halves of a bagel, and eat it like a sandwich. aurea-corde responds, "I aspire to reach this level of science."
December 11, 2025 at 3:38 AM
purplemath.com
"Sarah's house on my math test after I calculate its width to be 0.5 cm."

#mathematics #tests #invalid #wordproblems #realistic #reallife #mathhumor #purplemath
A house is shown. It has white sides, the windows have red shutters, the door is red, and the blue roof is very steeply sloped. The house may be of normal depth, but is extremely narrow. The caption across the picture says, "Sarah's house on my math test after I calculate its width to be 0.5 cm."
December 11, 2025 at 3:23 AM
purplemath.com
"Never ask a physicist or an engineer what they are doing, because they will tell you, upon which you will discover an entire piece of the English language you've never met."

#physicist #Engineers #jobs #englishvocabulary #mathhumor #purplemath
Debra Robinson says, "Never ask a physicist or an engineer what they are doing, because they will tell you, upon which you will discover an entire piece of the English language you've never met."
December 11, 2025 at 2:51 AM
purplemath.com
Miscommunication.

#romannumerals #ArabicNumerals #miscommunication #mathhumor #purplemath
A three-panel comic is shown, illustrating in-class messaging between the student (a small blue blob) at the chalkboard, and a person dressed as a Roman soldier (back in "Biblical" times?). Panel 1: The blue blob has been given the addition exercise "1 + 1 =", and the blob has the task of filling in the answer; that is, the value to which 1 plus 4 equals. Blob is glancing back over his shoulder at a friend, in hopes of a hint. Panel 2: Blob's friend is the centurion, who holds up his index finger and middle finger, similar to the "'V' is for 'victory'" sign. Panel 3: Blob turns back to the board, and writes down "2". (The joke being, of course, a reference to Roman numerals. Blob misunderstood Centurion's Roman-numeral for 5 as being instead the simplest way to indicate the value "2".)
December 11, 2025 at 2:44 AM
purplemath.com
Decidedly weird.

#opticalillusion #illusionfun #illusions #purplemath
A three-by-three grid of blue-ish dots is shown. The background is muted gray-ish blue. Oddly, the dot on which you concentrate will appear a darker purple. And this color change will follow you! If you look at a different dot, then the new dot will turn purple, with your original dot returning to its original color.
December 11, 2025 at 2:27 AM
purplemath.com
#bots #Verification #mathhumor #CAPTCHA #MathHumor #purplemath
A three-by-three grid is shown. Each of the nine squares contains a mathematical expression. Going left to right and then top to bottom, the expressions are: e^2, 6/8, infinity, 4!, sqrt(21), log_4(24), sum from i=2 to i=4 of i, integral from 2 to 9 of x dx, and finally (5π)/5. The grid is one of those "tests" to confirm that you're a human rather than a bot. The header directs the user to "select all the squares in order of least to greatest. (At bottom right, there is a "verify" button.)
December 11, 2025 at 2:20 AM
purplemath.com
The picture shows green swirls of repeated patterns. The caption labels this as "Naturally occurring fractal patterns in Romanesco broccoli (Brassica oleracea)".
November 22, 2025 at 8:15 PM
purplemath.com
[*squints*] Yes, *all* the details, please.

#science #discovery #disco #discoball #purplemath
A news clipping is shown. Two happy men are shown smiling into the camera. They are at sea, standing on the deck of a fishing vessel, and are holding up a scallop in their gloved hands. Above this picture is a headline and sub-head: "Accidental discovery that scallops love disco lights leads to new fishing technique: Scientists hail breakthrough that could maximize catches while reducing damage caused by fishing" Above the news clipping, the poster has requested, "Walk me through the scallop disco 'discovery' & don't leave out any details".
November 22, 2025 at 8:06 PM
purplemath.com
What it's like to be famous in mathematics.

#mathhumor #mathematician #fame #purplemath
Reporter: What is it like to be a famous mathematician? Mathematicians: [A picture of an eager-faced man speaking to the camera] In maths, fame means every century, someone will look your name up in an obscure book.
November 22, 2025 at 7:49 PM
purplemath.com
Bad Math Jokes

#mathhumor #functions #Notation #puns #purplemath
A one-panel comic titled "Bad Math Jokes". Two stick-figure people are talking. The figure on the left says, "I don't like maths." The figure on the right replies, "f(x) not?"
November 20, 2025 at 7:29 PM
purplemath.com
The Academic Path

#xkcd #mathhumor #academia #AcademicSuccess #purplemath
A one-panel comic, titled "The Academic Path". Centered in the comic is a square that has been split, vertically and horizontally, to form four smaller squares. Above the left-hand column is the title "Acts like they have no idea what they're doing". The right-hand column is titled "Acts like they know what they're doing". To the left of the top row is the title "Has no idea what they're doing". The bottom row is titled "Knows what they're doing". The four small squares are filled in, starting from the top left and going clockwise, with "Grad student", "Post-doc", "Assistant professor", and "Tenured professor". A red line traces the academic path; it starts in that top-left square, moves through the squares clockwise, and ends with an arrowhead at "Tenured professor".
November 20, 2025 at 7:20 PM
purplemath.com
What is the biggest number you can make by moving exactly two matches?

#matchstick #matchstickpuzzle #number #mathhumor #purplemath
The number 508 is "written" with matchsticks. Below, the reader is given the following challenge: What is the biggest number you can make by moving exactly two matches?
November 20, 2025 at 7:04 PM
Reposted by Purplemath
ejanearan.bsky.social
Wow!

#geology #rocks #jasper #sandwich
geologywonders1 says, "An absolute insane piece of willow creek jasper". In reply, Blue Heron Farm says, "I'm sorry, but I need you to see this rock that looks like a sandwich that I just found on Instagram". The picture shows the smooth flat of interior of a rock, light brown at top and bottom, with coils of vegetable green and lunch-meat pink. The rock looks exactly like a stuffed club sandwich.
November 13, 2025 at 8:06 PM
purplemath.com
ChatGTP fail

#AI #ChatGPT #ChatGPTFail #decades #half #mathhumor #purplemath
A ChatGPT query is shown. Q: What's half a decade? ChatGPT: Half a decade is 5 years divided by 2, which equals 2.5 years. So, half a decade = 2.5 years.
November 19, 2025 at 10:12 PM
purplemath.com
"Study hard what interests you the most in the most undisciplined, irreverent and original manner possible."
On the left-hand side of the image, Richard Feynman, a famous physicist, is shown teaching, with a blackboard behind him. On the right-hand side, Feynman is quoted as saying, "Study hard what interests you the most in the most undisciplined, irreverent and original manner possible."
November 19, 2025 at 10:08 PM
purplemath.com
I don't think it works that way....

#darkmatter #astrophysics #physics #physicists #math #Mathematics #arithmetic #mathhumor #purplemath
A three-panel comic. Panel 1: A sad cartoon face is shown at left. To its right, red text shows the equation "1 + 1 = 3". Below the equation is the question, "Calculations don't add up?" Panel 2: A grinning cartoon face is shown at left. To its right, the equation has had a black "1" added, so now it reads "1 + 1 + 1 = 3". Below, it says, "Add a hypothetical 'dark number' to account for inaccuracy." Panel 3: The grinning figure is now shown giving an approving "thumbs up" gesture. The text says, "Now you're doing math like a physicist!"
November 19, 2025 at 9:58 PM
purplemath.com
#mathhumor #e #numbers #decimal #purplemath
A text conversation is shown, with the first texter's messages shown in gray text bubbles and the replier's messages shown in blue bubbles. Gray: yo when are you going to the party Blue: I'll be there in e hours Blue: 3* [!] [Not delivered] Gray: yo it's been 2.718 hours and you're still not here where are you Blue: wdym 2.718 hours [Then, after noting that the correction from "e hours" to "3 hours" was "Not delivered", and that the value of the number "e" is approximately 2.718...] Blue: oh...
November 19, 2025 at 9:49 PM
purplemath.com
I don't think I've met the dude....

#scatterplot #graph #Statistics #regression #testosterone #intelligence #IQ #correlation #purplemath
A scatterplot is shown, with most points concentrated in an oval, wider than tall, which has generated a straight-line regression that decreases somewhat from left to right. The horizontal axis is labeled "IQ", with a scale that goes from 40 to 160. The vertical scale is labeled "Testosterone (nanograms per deciliter)", with a scale that goes from zero to 1700. The straight line is labeled as "Linear Fit (R^2=0.19)". The regression line shows a negative relationship between intelligence (as measured by IQ) and a man's testosterone. In other words, the greater the testosterone, the lower the intelligence, and vice versa. The graph's header reads "Testosterone vs IQ: Sample from 15,439 Natural Men, from the Nat. Long. Study of Adolescent to Adult Health (Add Health, Wave 5, 2018)". In the scatterplot, there is one point, clearly an outlier, near the top right corner of the rectangle bounding the data points. In other words, there was, within the data set, one man with a very high measure of testosterone who was also, contrary to the rest of the data, very highly intelligent. Above the graphing area, poster "amrit" says, "I think about this dude all the time".
November 19, 2025 at 9:36 PM
purplemath.com
The difference between "percentage" and "percentage points".

#percent #percentage #percentagepoints #mathematics #Purplemath
Post by hello-kitty-senpai: Here's the thing you gotta understand about statistics. "Increases your chances by 80%" does not mean "there is now an 80% chance". If your chances were previously 10%, your chances are now 18%, not 90% [or 80%]. If your chances were roughly 1%, they are now just slightly less than 2%. That's how it works.
November 13, 2025 at 6:18 PM
purplemath.com
Math and history.

#mathematics #math #Babylon #Babylonian #sixty #numbers #Purplemath
A man is shown in an "ancient times" environment. He is bearded and wearing a bland robe. He is bent over some sandstone blocks, many covered in carvings that appear to be cuneiform. He appears to be carving a groove into the top of the block in front of him.
November 13, 2025 at 6:09 PM
purplemath.com
Limits and infinity are weird.

#limits #area #perimeter #circle #square #approximation #circumference #pi #piequals4 #purplemath
A six panel comic, with two frames in each of three rows. Panel 1: Draw a circle. (A circle is shown, with diameter d = 1, having a red perimeter, and filled in with light blue.) Panel 2: Draw a square around it. Perimeter equals 4. (A black square has been drawn around the circle.] Panel 3: Remove corners. Perimeter is still 4. (Each of the corners of the original square has been cut out, with the "corner" of the removed portion touching the circle.) Panel 4: Remove more corners. Perimeter is still 4. (The process is repeated between each pair of points that touches the circle.( Panel 5: Repeat to infinity. (The corner-removal process is shown at a much later stage, with the black jagged-edged rectilinear line now very close to the red circumference of the circle.) Panel 6: π = 4. Problem, Archimedes? (A grinning cartoon face is shown.)
November 13, 2025 at 5:50 PM
purplemath.com
"I like your weird brain very much." 💜

#brainhealth #weird #weirdos #purplemath
Two cartoon figures are shown. The figure on the left is patting on the head the figure on the right. The left-hand figure is saying, "I like your weird brain very much."
November 13, 2025 at 5:10 PM
purplemath.com
If clocks had been invented in the Southern Hemisphere, they'd have been built backwards from their current form. Why?

#sundial #clock #clocks #clockwise #history #romannumerals #purplemath
A sundial is shown. Because the sundial is in the Southern Hemisphere, the Roman numbers are going from right to left, opposite "clockwise" orientation.
November 13, 2025 at 5:03 PM
purplemath.com
Not a berry.

#botany #berries #purplemath #ScienceHumor
A one-panel comic entitled ."Halloween Botany". Four food items are shown, two in each of two rows. Going left to right and top to bottom, we see: A drawing of a raspberry, captioned "Raspberry: Not a berry". A drawing of a blackberry, captioned "Blackberry: Not a berry".. A drawing of a strawberry, captioned "Strawberry: Also not a berry". A drawing of a pumpkin, captioned "Pumpkin: Is a berry".
October 14, 2025 at 1:44 AM