MITiplication by Yan Z. '12
This entry contains one multiplication problem.
It was sometime during Act III of finals study week, in the pressure-cooker minutes before the curtains fell on our loose-spined textbooks and leafed-over study guides, that I asked aloud, “What is 7 times 47?”
In the space of the paragraph break above, you’ve probably calculated the answer, brewed yourself a cup of coffee, and commented “FIRST!” on my blog already. Great. We’re now ready to play a short psychological game. A private, procrastinatory research project that I adopted in the dwindling time before my first final showed that everyone* interviewed found the answer by one of three methods:
*i.e., everyone likewise procrastinating in one of Random Hall‘s lounges at 11 pm on Sunday.
1.Take 7 times 4, multiply by 10, add 7 times 7.
2.Take 7 times 5, multiply by 10, subtract 7 times 3.
3.Imagine a piece of paper, do cross-multiplication on your imaginary piece of paper with your imaginary pencil and eraser, and then proudly circle your imaginary answer. Ex: “7 times 7 is 49, drop the 9, carry the 4 to the next column, 7 times 4 is . . .” etc.
My hypothesis is that if your first instinct was Method 2, you’d also show a natural talent for parallel parking. Rationale: when evaluating the most direct route to your goal, be it the answer to a multiplication problem or the cathartic resolution to a neck-twisting parking maneuver, you don’t hesitate to overshoot your target and then back up until you’re perfectly centered. (By the same reasoning, people who followed Method 1 probably had trouble getting their driver’s licenses; people who followed Method 3 should stick to riding bicycles.)
It remains unclear whether this theory has valid support, but unexpected anecdotal data collected during the study has lead the author to vow against carpooling with certain denizens of Random Hall.
Since I’ve been having difficulties making Nobel-worthy discoveries in either of my summer UROPs this week, I’ve decided to resurrect my parallel-parking-mental-multiplication (PPMM) experiment. Comment with (1) your natural method of calculation and (2) how often you rear-end other cars (if applicable). Data collection via blog comments is the new trend in science, so I’ve heard.
A subtle yet heartbreakingly crucial property of summer projects is that they tend to exist in pairs. Or triplets. Or where n-tuplets, where n = n+1 for every time that someone batters down your self-restraint with an email like:
I conclude with a sampling of current projects filed under “Continued self-delusions of infinite free time”:
7. Rebuild the bridge from pika‘s balcony to pika’s treehouse.
14. Deploy a Rube Goldberg machine in the basement, preferably designed around the theme of vegetarianism and explosives.
21. Eat at every single dim sum restaurant in Boston. (Alright, I will admit that this isn’t a project so much as a function of my tidal desires to consume entire subrainbows of the culinary spectrum, especially compelling on Saturday mornings.)
28. Read the complete published works of David Foster Wallace, then metamorphosize into David Foster Wallace.
35. Take more photos with metaphoric gravitas, so that I can start a gallery collection and open a critically-acclaimed art exhibit at the List Center. To start:
(It’s a fence, and there’s a sky behind it. It represents the human condition, or something.)
42. Start running up to 10 miles regularly. (I’m at 6 miles right now.)
49. Witness the finishing of a 6000-piece jigsaw puzzle, a retina-melting endeavor started last night as a peaceful (thus far) collaboration between pika and WILG, two of MIT’s independent living groups. The puzzle itself is currently living in WILG’s 2nd-floor lounge and, until completed, will remain an effective hindrance to activities like vacuuming.
56. Bike along the entire shoreline of Boston’s Inner Harbor, or until I discover this to be an impossibility.
View Larger Map
Arathi and I made a reasonable effort on Wednesday. I hitched up the rust-barnacled, long-abandoned bicycle that I befriended in the humid depths of pika’s garage (single-speed, one functional brake, cracked turquoise paint, perfectly unlovable) and we ET’ed ourselves into the cinematic sunset, pedaling along the Charles River, past the Science Museum, past wherever-we-originally-intended-to-go, around regally-named hotels, through Boston’s touristy Colonial-era marketplaces and a irresistibly charming block of Little Italy (gelaterias, pastry shops, open-windowed pizza restaurants- all adorable in the way that somehow makes you want to re-watch The Godfather), up Beacon Hill, against rush-hour traffic, and finally:
On second thought, let’s add “Learn to parallel-park” to the list.
I used method 1.
I use method 2 (or some variation of it) to factor license plate numbers.
I almost killed a man one day (while I was driving).
I used method 1 and passed my driving test fine and have never had an accident. But then again, parallel parking wasn’t on my driving test or even covered during driver’s ed.
My career in censorship is now over.
@ Rachel:
I’m also surprised at the number of Method 1’ers. When I did this in Random, the majority of people used Method 2. You could be right.
I used method 1. I’ve never rear-ended anyone but I have personally been rear-ended twice. I had no trouble getting my driver’s license at all, and I’ve never had trouble parallel parking (as long as I can back into the space.)
I used method 1. I’ve never rear-ended anyone but I have personally been rear-ended twice. I had no trouble getting my driver’s license at all, and I’ve never had trouble parallel parking (as long as I can back into the space.)
I multiplied 7 by 45 (by multiplying 90 by 4 and subtracting 45) and then added 7×2. So I guess I’m not cut out for MIT (or at least MIT’s procrastinating lounge, if I may call it that) after all.
I don’t believe I’ve ever parallel-parked in real life, so I don’t think I’d be particularly good at it.
I feel like Method 1 or 3 are more intuitive in general…or maybe it’s just me. I don’t like substracting numbers>10 in my head. Seriously, who likes to substract 21 from 350?
so then not many people would be good at parallel parking in this world…which might be an accurate statement : )
I used #2 at first, got an answer. Double checked with #1.
Now for my driving. I’ve never actually parallel parked, though I learned the theory through my driving instruction videos. Also, in Texas, if your driving instructor (my mom) passes you, you don’t have to take a test. However, I’ve never had a wreck.
I don’t know if that’ll get you anywhere.
Method 1, and I’ve got quite the aptitude for parallel parking. My test-giver-woman-person even commented on how well I did =D
Method 4: Multiply 47 by two and add it 3 times. Then add 47. Maybe this is why I’m not 18….
But I can parallel park.
Anyway, I WANT TO BIKE BOSTON HARBOR SOMETIME.
I used method 2, though the method I use for various simple multiplication problems oscillates among all 3 depending on the mood I’m in, and while I have never come close to an accident, I find parallel parking extraordinarily difficult if there are two cars around the spot I want (it’s easy otherwise… but my dad finds it easy no matter how tightly packed in the spot is =.=” Though he used method 3 this time and said that he also changes how he multiplies on a whim, hahahah).
Was it necessary to censor Arathi’s last name? I mean, I’m willing to bet there’s only one in Pika, and there’s kinda a web page that comes up from a search about that :3
What a nice sense of humor.
I have a question about admissions.
I watched more 8.02 (I should mention talking about taking shirt off in front of mirror has also witty sense of humor).
I finished 2 semesters in my university. I would love to learn like the way I see in the video lecture. I believe memorizing is just waste of time.
How can I apply, and if I apply as transfer does it mean I’m going to miss some of the MIT courses?
Hey Yan– I’m not sure if you know this, but um, you censored her last name in the email header but not in the “Invite Arathi ____ to chat” in the bottom of the email >.>
Any method other than Method 3 is too intellectually taxing for me, and I applaud anyone who utilizes Methods 1 and 2, lol. (seriously, haha I would never think of using something other than brute force when it’s easy to do)
But of course, 998 x 89 would be a different story.
I didn’t use any of those, I kept reading to see if you would give us the answer.
Then I figured I would have used Method 3. I’ve never tried parallel parking, but have never rear-ended anyone!
Used method 1. Almost have backed into a car. Once. Have hit the sidewalk several times.
I used method 3 and I still ride my bike. Great post, nice pics. Gave me something to read.
Check out the Boston Bike Map – http://www.cityofboston.gov/TridionImages/BikeMap_tcm1-3455.pdf It might be useful to you!
Shoot, Yan, I’d definitely do it the first way and I’m hoping to get my license this summer.
Hm, interesting observation. I use a superposition of methods 1 and 2. Also, my ability to parallel park is also simultaneously terrible and amazing, since I have never parallel parked before, so my skill is still yet to be observed.
Yan- I use Method 2 usually, and would rather self-amputate without anesthesia than parallel-park. Neat pics! How’s the telescope coming?
I imagine that I’m conversing with an illustrious person and that, as I walk away, I nonchalantly ask “Hey, what’s x times y?”
I did method 1 and passed my learner’s test with flying colors!
I could probably parallel park assuming that both adjourning spaces were empty and I was allotted unlimited time. Reverse driving is a three-step process for me: point in the direction I want the rear end to go, turn the steering wheel, and incrementally ease up on the brake pedal, previously pinned to the floor by the greatest force I can muster from that slightly awkward angle.
Fortunately, as a part of my campaign against insomnia, I have no intention of getting my license. I’ve decided the mere knowledge that I won’t be behind a steering wheel will help thousands sleep more soundly. This admittedly played more than a minor role in my decision making:
CHARACTERISTICS OF NIKI’S DREAM COLLEGE
(in order by length, not necessarily importance)
1. I must be able to get anywhere within 10 to 20 miles easily combining public transportation and my feet (bike pedals will be acceptable assistance; gas pedals will not.)
2. I want to be surrounded by people who are all smarter than me and have done things I’ve never imagined.
3. Lots of languages (cross-registration availability is ok.)
4. Chinatown.
Check, check, check and check, I do believe. =]
(Although I haven’t found online evidence of a noraebang/karaoke box; does anyone know of one?)
Method 1 – though initially I was amazing at parallel parking, the ability diminished until I found the need to go to the library [which has only parallel parking]
WOW! Your photography is fabulous!
I used Method 1 and have yet to rear-end another vehicle. Bumped into the sidewalk plenty, though…
Load Mathematica, let it do it.
Ask Google.
Ask WolframAlpha.
Ask somebody else.
Use my TI84.
Guess.
Define as “x,” carry it through and come back later.
I used Method 1 and failed my Driver’s Test twice.
Method 2 and have yet to rear-end a car- Currently wondering why the majority of commenters are Method 1 users, shouldn’t the distribution be more equal? My hypothesis? They disagree with your PPMM hypothesis and want to add data points to the contrary while Method 2 users are pretty happy with the null hypothesis.
I imagine Snively pulling up to the parking space, getting out an iPhone, and looking up “How to parallel park” on wikihow.
I would have said “about 350” but then used method one.
but parallel parking is easy, with practice.
@ Karl:
On second thought, I did encounter a few other people who approximated and rounded to the nearest 10’s. If they apply the same standards of “close enough” to driving, I’m going to pass if asked to carpool with them.
Method 1, though I start out with method 3… no accidents or even close encounters (that were my fault) so far. :D
I’m a decent parallel parker(?), but I had a bit of trouble backing the figure eight to begin with… if that counts.
method 3 and I am regularly complimented on my parallel parking abilities.
maverick?
I used method one(although backwards, 7×7 then 7×40, if you care).
I passed my driving test first try (whether or not that had anything to do with it being the last test before the end of the year remains unconfirmed. I got fewer points off for stalling than my older brother, but stalled more than him. And they gave us petit fours), and am somehow able to parallel park fairly well. I don’t really understand this myself, as my parallel parking method involves a good deal of blindly backing up and hoping. But I somehow manage to end up straight every time. Ironically, I never end up straight in pull in parking spaces. I’m lucky if I even end up between the lines.
I prefer rounding off the number to the nearest ten and then employing first or second method whichever applies …
so where would that place me as a driver …
did your hypothesis said something about hybrids such as me Yan ??
Method 2 ftw.
I started learning to drive then gave up before I got my license… I’d say I’m decent at parallel-parking but not a great driver in general.
I used method #2 and I actually was never taught how to parallel park. I naturally picked it up as I did with all other aspects of driving. I have not had an accident yet!
Method 1, passed driver’s test no problem
. I love your blogs. You are an excellent writer.
I used method 1, and I approach parallel parking timidly. This summer’s going to be fun – parallel parking every day!
I did method 1, and I failed my first driving test. I completely agree with your conclusion.
Method 3 as always. I never understood those other multiplication methods.
Kinda method 1… 40*7 + 7*7 close enough
Haven’t hit anything/body yet
And so the results appear to validate . . . absolutely nothing.
i did method 3. well it come to me instinctively and fast. and i wouldnt carpool with myself either, YET. but my answer’s CORRECT
You must take into account the bias for self reported data. Are these self declared wonderful parallel parkers actually good drivers?
I used method 1. Backed into a car in a parking lot once, realized that I mixed up “reverse” and “drive”. Had to take the driving test twice after I hit the curb when turning. I periodically hit sidewalks
I use method one, and am scared to take the driving test.
I used #3 and got a 95 on my road test first time
I used none of these methods. I just simply did the multiplication in my head. It wasn’t that difficult to figure it out…. I haven’t taken my Drivers ED test so I am uncertain if this experiment applicable.
I use method number 2 all the time I am an amazing driver.
24 years of driving not a ticket or accedent over 6 Million miles of perfect driving.
I guess it dosent hurt that I have a masters in enginering from Colorado school of mines http://www.mines.edu/ and was at 1 time in my past a wiz at math.
I am now strugling with it.
I still do math in my head, tho it was and is my down fall. Showing your math kills me LOL.
Is this wrong? round up/down finalize answer then remove what you added/subtracted to get you answer?
I teach Math from time to time.
Children Know 1 thing and that is Money Penny to dolar and that all we need in math well the 50 cent piece is a little confusing for them LOL
Ok love ya all good luck new Class!!!
I hope my new Grades and my attemps to get in to MIT for next year are looked on with favor!
But of course, 998 x 89 would be a different story
HUM
Well the 998 is now a 1000 or 1
the 89 is now a 90 or 9
9+ the zeros I dumped that would be 90000
well I stole 1 998 times so got to get rid of those. and I stole 2 89 times.
Well poo more math.
The 89 is 90×2-2 or 178+998-90000=88822 LOL
So my math is odd
Yikes… I used method 1… I start driving lessons on Monday! =|
That being said, I drove around the park with Mommy yesterday afternoon… and nearly killed a man with dreadlocks on the way back home. =|
Crap, I used Method 3. How did I get into MIT…
Oh, I know. It was with my rhyming talent.
Method 1, but backward, I multiplied 7 by 7 and added that to 7 times 40. I’m at MIT and I don’t think I’ll ever get a license, I’m getting a chauffeur, sorry. Maybe a motorcycle license.
@ rose
who likes to substract 21 from 350?
Well First you need to simplified the equation.
You have been taught to read left to right.
We all want to make things easy right.
well 350 is realy 300 and 50
As well 21 is 20 and 1
Break things down.
50-20=30 and 30-1=29 and 29+300=339
Do math like you read Left to right
a=1+z-c*k/2
You read it left to right do it left to right.
Dont give me the answer LOL not fair to the rest of us lol
Woot got my admissions Pack today.
@
YAN
What Math Method of madness do you use?
350 (7×50) – 21 (7×3) = 329 (7×47)
I am good at parallel parking..
You have very nice procrastination skills, I must say.