When I was in middle school, I had a classmate who would look at trigonometric functions and yell, "I will never need these!" A lot of us had similar thoughts but wouldn't say them out loud. But there's a subreddit that proves otherwise.
'They Did the Math' is full of useless yet fascinating calculations for all of us normies who can't crunch the numbers ourselves. From how many flies it would take to lift an average person to how fast a Godzilla-sized snail would crawl, here are some of the most interesting questions—and answers—we found scrolling through its feed.
#1 How Fast Would A Snail This Size Go?

innnerness: If we take it literally, assuming the snail is roughly the height of a five-story building (say, 15 meters tall), that’s about 1,500 times larger than a typical garden snail (~1 cm tall). Speed scales roughly with the square root of linear size if muscle power and proportions stay the same. So: Average snail speed: ~0.03 mph (0.048 km/h). Square root of 1,500 ≈ 39. 0.03 mph × 39 ≈ 1.2 mph (about 2 km/h So, this Godzilla-sized snail would crawl at a slow walking pace, fast enough to make “Walk for your lives!” actually sound like decent advice.
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46points
#2 Is The Math Here Accurate?

whynotthebest: Math is correct but the words are not. This is similar to stating that the 2010 federal minimum wage of $7.25/hr could buy you 72.5 Bitcoin after an hour, and since 72.5 Bitcoin is now worth $7,568,659.25, then federal minimum wage was $7,568,659.25 in 2010.
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33points
#3 How Much Would The Cat Have To Weigh For This To Be True?

SecondaryWombat: So it looks like my laptop take about 50g of weight to press a key (Source: I put my laptop on a scale and pressed keys). Standing still a cat stands on all four legs (I am choosing to extrapolate the existence of this kitten's other back leg). So while not moving, with its paws on only one single key each (which we can see from the photo is not correct) the kitten would need to weigh 50x4=200 under 200 g. However, it looks like each paw that we can see is on a minimum of 2 keys and that changes things substantially. 2.5 keys/leg x 50 g/key x 4 leg/cat = 500 grams/cat, and look the units cancel, so that means my math is right. A 500 gram kitten is about 5 weeks old, and that also looks correct visually.
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27points
#4 Would 4 Balloons Be Enough To Lift That Small Boi?

electricsoldier96:
They did it on MythBusters, with 3500 balloons and a 44lbs child. If this is a 20lbs Dachshund, it would took 3500 / (44 /20) = 1590 balloons.
They did it on MythBusters, with 3500 balloons and a 44lbs child. If this is a 20lbs Dachshund, it would took 3500 / (44 /20) = 1590 balloons.
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26points
#5 Could They Actually Still Make A Profit?

e-war-woo-woo: Tesco is slightly over on Google figures for 2024 3128 million profit, 330,000 world wide employees = 9478 per employees. So if they paid 10k extra they’d be makings loss. But they could defo do 5k extra and still make a healthy profit.
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24points
#6 While Inspiring, Is This The Most Efficient Way To Move A Bookstore Around The Corner To A New Location?

Single_Blueberry: A human chain is probably the most efficient way if you HAVE to use this many people, because they would block each other if they moved. Could you do it just as quickly or quicker with much fewer people? Probably. More importantly though, it's fun to do it this way and a good opportunity to socialize.
ya_mamas_tiddies: This is 100% the most efficient way, as none of those folks are getting paid for this. What can be more efficient than free manual labor
ya_mamas_tiddies: This is 100% the most efficient way, as none of those folks are getting paid for this. What can be more efficient than free manual labor
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24points
#7 They Worked It Out Before They Worked It Out

shelmich: If his weight doubles every 3 months, then by the time he hits 10, he'll have doubled 40 times. So if he's 7.5 trillion when he's 10, then we can solve for his birth weight in the following equation: 7.5 trillion lbs = x * 240 This gives x = 6.8 lbs, a very reasonable birth weight.
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21points
#8 What Would Happen To The Turkey If You Did This?

jeffscience: This is 10x the estimated temperature at the site of the nuclear blast at Hiroshima. The turkey would cease to exist in any recognizable form.
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21points
#9 If You Made $7000 Per Hour Since The Birth Of Jesus Christ, When Will You Surpass Jeffrey Bezos, Current Net Worth. What About If His Net Worth Expands At Its Current Rate?

GIRose: Jeff Bezos' net worth, ~$210,000,000,000 210 billion/7000 = 30,000,000 hours to surpass him. There are 8,760 hours per year So ~3,424 years to catch up to Jeff Bezos' current wealth at $7000 an hour if it was expanding at it's current rate, literally never because it expands by ~$8,000,000 an hour.
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21points
#10 This Feels Untrue

UncleCeiling: There are about 13,500 McDonald's restaurants, each with an average of 50 employees (As per McDonald's 2023 numbers). A large McDonald's fry has about 80 fries in it (numbers seem to vary from 75-90 depending on where you are getting your fries, and it costs $5 (note that that's retail, not what the company actually pays) for a total of $0.0625 per fry. So if every employee (not just the ones on staff) ate a single fry every day it would cost the company $42,187.50 based on retail fry numbers. For individual stores, it wouldn't even average the price of a large fry.
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21points
#11 I’m Really Curious— Can Anyone Confirm If It’s Actually True?

escaping-to-space:
Aircraft carrier ~ 13
Billion American homeless ~ 800 thousand
High-density construction cost ~ $350/square foot
13B/800K = $16,250 available per person
Divided by 350/sqft = 46.4 sqft per person (of new construction)
So depending on exact construction costs or repurposing old buildings, you could get a ~5x10 room per person. Not enough to house everyone, but I suppose technically enough to shelter everyone. Since that room doesn’t have space for plumbing or kitchen, you might be able to construct for less than $350/sqft and then maybe squeeze out a bigger room or have some shared bathroom/cooking areas but that still isn’t housing.
Though, while I know we pump a ton of money into military, the price of one ship did give more per person than I initially would have guessed.
Aircraft carrier ~ 13
Billion American homeless ~ 800 thousand
High-density construction cost ~ $350/square foot
13B/800K = $16,250 available per person
Divided by 350/sqft = 46.4 sqft per person (of new construction)
So depending on exact construction costs or repurposing old buildings, you could get a ~5x10 room per person. Not enough to house everyone, but I suppose technically enough to shelter everyone. Since that room doesn’t have space for plumbing or kitchen, you might be able to construct for less than $350/sqft and then maybe squeeze out a bigger room or have some shared bathroom/cooking areas but that still isn’t housing.
Though, while I know we pump a ton of money into military, the price of one ship did give more per person than I initially would have guessed.
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19points
#12 Is This Even Remotely True?

Yes N64 cartridges vary between 4-64Mb
388x 64= 24,832Mb so 24-25Gb if they were all max size.
So they would easily fit on, especially once you account for the smaller games.
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17points
#13 If Every Person On Earth Went For A Swim In Lake Superior, How Packed In Would Everyone Be?

Appropriate-Falcon75:
The area is about 82,000 km2 , and there are about 8.2bn people on earth. Which means that each person gets about 10m2 . So, if you arranged people in a grid, there would be about 3m (or 10ft) between each person.
The area is about 82,000 km2 , and there are about 8.2bn people on earth. Which means that each person gets about 10m2 . So, if you arranged people in a grid, there would be about 3m (or 10ft) between each person.
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16points
#14 How Can This Be Right?!

A_Martian_Potato: This is a very well known mathematical problem. The post is correct. It's one every student in a undergrad level statistics course does. I won't go over the math to prove it, you can see that in the wikipedia page if you want, but the thing to keep in mind is that you shouldn't be comparing the number of people to the number of days in a year. You should be comparing the number of PAIRS of people to the number of days in a year. In a room with 23 people there are 253 pairs you can make. In a room with 75 people there are 2775.
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15points
#15 How Many Pennies Will Be Needed To Make This

STK_Pixle:
A penny made before 1982 is 3.11 grams and consists of 95% copper, so taking 95% of 3.11 is around 2.95 grams. 1 penny = 2.95 grams of copper There are approximately 454 grams in a pound, and Lady Liberty is made of 62,000 pounds of copper. 454/2.95 = 153.9, which would round up to 154 pennies for one pound of copper. 154 × 62000 = 9548000 So in total, you would need 9,548,000 pre-1982 pennies, or $95,480 in face value, to make a second statue from just pennies.
A penny made before 1982 is 3.11 grams and consists of 95% copper, so taking 95% of 3.11 is around 2.95 grams. 1 penny = 2.95 grams of copper There are approximately 454 grams in a pound, and Lady Liberty is made of 62,000 pounds of copper. 454/2.95 = 153.9, which would round up to 154 pennies for one pound of copper. 154 × 62000 = 9548000 So in total, you would need 9,548,000 pre-1982 pennies, or $95,480 in face value, to make a second statue from just pennies.
14points
#16 How Long Would This Take?

PolyPorcupine:
Spotify says it has 100 million songs and 6 million podcasts, average length of a song is 3 minutes, the average length of a podcast episode is 41 minutes, and the average amount of episodes of a podcast are 10. Also they have 350k audiobooks, at an average length of 10 hours. So you have 300,000,000 minutes of song And 2,460,000,000 minutes of podcasts and another 210,000,000 minutes of audiobooks. Totaling around 3 billion minutes of content. Calculating it's around 5707 years, if you listen to it at 5707x speed you'll be done in a year, easy. Though google also says that around 100K songs are added every day, so once you are done with those you'll have another ~300k minutes every day.
Spotify says it has 100 million songs and 6 million podcasts, average length of a song is 3 minutes, the average length of a podcast episode is 41 minutes, and the average amount of episodes of a podcast are 10. Also they have 350k audiobooks, at an average length of 10 hours. So you have 300,000,000 minutes of song And 2,460,000,000 minutes of podcasts and another 210,000,000 minutes of audiobooks. Totaling around 3 billion minutes of content. Calculating it's around 5707 years, if you listen to it at 5707x speed you'll be done in a year, easy. Though google also says that around 100K songs are added every day, so once you are done with those you'll have another ~300k minutes every day.
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14points
#17 [request] Did They Actually Do The Math?
![[request] Did They Actually Do The Math?](https://wsrv.nl/?url=https%3A%2F%2Fstatic.boredpanda.com%2Fblog%2Fwp-content%2Fuploads%2F2025%2F12%2F6942c7895e862_useless-interesting-calculations__700.jpg&w=3840&q=75&output=webp&fit=cover)
Ritterbruder2:
A sphere has the lowest surface area to volume ratio of any shape. It’s going to have the lowest glaze to dough ratio of any pastry.
A sphere has the lowest surface area to volume ratio of any shape. It’s going to have the lowest glaze to dough ratio of any pastry.
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14points
#18 Could This Be Accurate?

Warm-Finance8400: That would translate to the average person being drunk 0.7% of the time. A week has 168 hours, 0.7% of that would be ≈ 1.2 hours per week drunk. Seems reasonable to me.
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13points
#19 Is This True?

Public-Eagle6992: I‘m not sure how exactly the statement is meant so I’ll interpret it one way but also state other ways how it could be interpreted. "The ten richest men…" could either mean each of them individually or all of them combined. I‘ll go with individually. "Their riches wealth" I assume this means net worth "Richer than 99%" could mean the wealth of the 99% combined, could mean the average wealth of the 99% or could mean the highest amount of money anyone in the 99% has. I‘ll go with highest Wealth of 10th richest person: 121 billion. -99.999% that’s 1.21 million. 1.1% of adults have at least 1 million, so when having 1 million, you can still be in the lowest 99%. So it might be true, it’s close.
12points
#20 Is This True? Only 33 Wins?

wayoverpaid: This assumes a single elimination, best of one tournament. Say something like rock paper scissors or a coin flip. You need one round for the finals. So one game for the finals. Semifinals has four people, quarter finals has eight people. Each round cuts the field in half. The winner only needs to win one round from that game. With 33 rounds, you get 233 people. That's 8,589,934,592. World population is under 8.3 billion. So the winner MIGHT get a bye in the first round, and only have 32 games. But 33 games guarantees the win.
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12points


