Fein US posted a math riddle to their Instagram channel, shown above.
So, what’s the answer?
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They’ll reveal the correct answer tomorrow.
No, it’s not 42.
Fein Tools Math Riddle
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Marty
16
John B
Agreed
bjacob
I agree with his agreement.
bjacob
No I don’t. I just realized the last one has multiplication. 60.
Clifford Alloway
I had to put my glasses on and when I did it looks that 60 is correct…
fred
If you consider:
A= tool
B= battery
C= blade
3A=30 or A=10
1A+2B=20 so B=5
1B+4C=9 so C=1
A+B+C = 5+1+10 = 16
But if you consider the tool as having a battery that is considered separately – then the equations look like this:
3(A+B) =30
1(A+B) +2B = 20
B+4C = 9
so from the first equation A=10-B
substituting into the second equation:
10-B+B+2B= 20 or B = 10 and then A =0
Then if 10+4C=9 = C= -0.25
So in this scenario
10 + 0 +(-0.25) = 9.75
fred
Forget what I wrote above
Should have looked at the last line with multiplication sign.
Case 1 >> B + C x A = 5+1 x 6 = 60
Case 2 >> 10 + 0.25 x 0 = 0
fred
Case 2 should have been >> 10.25 x (0+10) = 102.5
Stuart
Since A + B is constant in all instances, appearing paired together, it can be considered a single variable, D.
Whilst there is enough to solve for A, if you consider that the tool is described as A + B, you don’t need to.
If you sub in B = 10 – A into the second equation, you get:
A + 3B =20
A + 30 – 3A = 20
10 = 2A
A = 5
B = 5
Same as if A+B = 10, or D = 10.
Considering the bare tool as separate from the battery-equipped tool just makes more work.
bjacob
No I don’t. I just realized the last one has multiplication. 60.
MichaelHammer
17
MichaelHammer
Dag! 25
palm
The answer is 15. Math order of operation. 10*1 +5.
Wayne R.
You’re the first one (here, anyway) to get the math right. Winner! Of what, I don’t know, but your teachers should be proud too.
jay dawes
17
Johnny4
The problem included some observational and order of operations subtleties which can easily trip you up.
List of incorrect answers and why:
16 – did not notice the multiplication symbol
25 – did not notice the single blade
17 – missed both single blade and X
60 – incorrect math adds before multiplying
70 – incorrect math and missed the single blade
Will
Yep,10 for the supercut,5 for a battery and one blade equals 1 so it’s 16.
Johnny4
Incredible. After all the explanations how can you possibly still think the answer is 16?
Brett
25
Alexis
Seconded
Alexis
Crap nevermind, I just saw what they did, the answer is 15.
Mike
Yeah i just saw that too. 15 gets my vote
Jag Hundal
thirded
Jag Hundal
i stick to 25
Justin
Count the multitool blades.
Stacey
Yep
Stacey
Definitely 25
kdv
I’m going with 16 as well
Grizz
25 is the correct answer. Order of operations is multiplication/division before addition/subtraction. The expression is 5 + (2 x 10).
Corey
17.
Corey
Immediately realize that while I spotted the trick, I applied it wrong in my final step haha I rescind my previous answer and second Marty?
Corey
And still messed up pemdas. Jesus, point taken, Stuart haha
Ewoud
10+10+10 = 30
10+5+5 =20
5+2+2=9
5+2=7 7×10 = 70
Leo Bauer
70
Struggleville
17. 100%
Wayne
There is a multiple, so 70
Wayne
Forgot order of operations lol
Doh- 25
Allen Wilson
Hey guys, there’s only one correct answer. It’s all in the details and correct order of math.
Look at the scrapers, it’s:
2 scrapers + 2 scrapers = 4
So:
1 scraper = 1
On the last line, multiplication trumps addition in the correct hierarchy of math operations. So, last line is:
(5) + (1×10) = 15 Final answer
Harry
70
Matt S
15
Matt S
10+10+10=30
10+5+5=20
5+2+2=9
10+(1*5)=15
csroc
Yep. Tricksy because I didn’t see the change in the number of blades on my phone screen without looking closely.
Marty
Ooo didn’t notice the multiplication sign!!
Austin S
Agreed
Michael Polk
The correct answer is 15. I am sure a lot of you will come up with different answers but I will explain to you why this one is correct…tomorrow 🙂
TonyT
Yup, that’s what I got…order of operations and count the number of multi-tool blades.
Davin
It’s 15 guys. Remember order of operations. (PEMDAS)
CraftsmanForever
25 is the answer
Ryan
Yep, $25. Multiply the 2×10 then add the 5.
Ryan
My bad, didn’t notice there’s multiple blades stacked on line 3. Answer is 15.
Tom Magill
60
sellers
you are correct
Michael Polk
And too bad there is no prize lol
Brien
15
Tom Magill
Ah… order of operators.
Change mine to 15
Paul Dajewski
60
Luis
70
Josh
15
Willson
60
And Bob’s your uncle.
There is no spoon.
The cake is a lie.
Craftsman forever
25 is the answer
Addison
It’s Fein so infinity! And the HSS cutter is dull.
Tim
60
Justin sherriff
10+10+10=30
10+5+5= 20
5+2+2= 9
5+2=7×10= 70
70
Justin sherriff
60
5+1×10=60
4 blades on line 3 only 1 blade in the riddle
BenV
15, the multiplication takes precedence over the addition…
Noli
This guy gets riddles Answers 17 everyone
Nol
Edit**
It’s 60 ohh man now I’m confused.
Henry
The answer is 15
Thank you Mr. Towne (my HS math teacher)!
Brian Harris
15
Don
17
Scott Davis
The answer is 15.
Ryan Rich
25.
10×2 +5
Don
Oops 70. Missed the “x” on the last question
PHILIP JOHN
Its 15.
It would only work out to 60 2 other ways… if it was dewalt or Milwaukee and then I would say give me 60 ( more better tool.)
Michael
60!!!!!!!!!
Brett
Had to go to the actual computer to see the number of blades everyone is talking about (tablet + old eyes = ahhhh crap I’m wrong….)
10 + (1×5) = 16
mumble mumble mumble
🙂
ChrisP
1×5=5. So
10+(1×5)=15
Raoul
15
Brett
holy crap now I can’t even add when I can see LOL
15
MacLean
60
Vards Uzvards
5+1+10=16
Vards Uzvards
Scratch the above! 🙂
5+1×10=15
Math is hard!
Scott K
15. PEMDAS + Pinch to Zoom for the win!
A W
15.
Doubling the OMT blades is sneaky.
evadman
10+10+10=30
10+5+5=20
5+(1+1)+(1+1)=9
5+(1*10)=15
Harry Klein
76
Darth
17
Darth
Changing to 16 now that i see 2 blades on the 3rd line amd only 1 on the 4th.
Harry
650
Mike
The whole 2 blades vs 1 is kind of cheating on the trick. I never noticed till I saw someone mention in it and I zoomed in. Small detail on small screens like that is hard to see. 15, the order of operations trick gets people every time.
andy
The correct answer is in dollars, and the number is frighteningly high.
Corey
This may be the best answer lol
Johnny4
All the incorrect answers after MattS explanation amuse me.
Louie Orama
I’m going with 60 as well… First line tells you that the Oscillating Tool is 10. Second line tells you that the battery is 5. Third tells you that each blade is 1. So it is 5+1=6 x 10 = 60.
Ryan
Multiply before dividing. It’s actually this: 5+(1×10)
Lukas
15 if you do it the meme math way. I’m going to argue that there isn’t enough information. 3 equations with 4 unknowns. The single Fein and double Fein blades should be treated as separate variables. If I were to say that W=10 would you assume that V=5 just because a W looks like two Vs? Probably not.
Alexis
If W = 10 we have no way of knowing V, but one could make a strong argument for U = 5
Lukas
Well I’m just going by the appearance because that’s what we’re doing in this Fein riddle. I still don’t agree if we go by the name of the variable. Letters weren’t named with algebra in mind.
Adam
15
5+1*10. Multiplication always comes before addition unless there are parentheses. Therefore, 10*1=10, then 10+5=15
Kurt
60
Brian A
The answer is a lot of people are bad at basic math.
Or if you’re smart enough to get the right answer (15) you are to smart to pay Fein prices.
Adam spiller
The answer is 16
Altan
Was it made in Germany also?!!!
Cary
17
Rick H
Answer is 70
Adam
15
Higgo
Wow! I would not let a majority of you do work on my house 🙂 Our contract would have to have a lot of verbiage re: who’s responsible for the cost of material shortages/overages.
Clint
25
5+(2*10)
Clint
15
Sorry, poor eyesight, did not see the bunched up blades.
Jerry
15
OldDominionDIYer
25
5+2X10
OldDominionDIYer
Oops there’s only 1 multi-tool blade in the last row so it would be:
(1X10)+5=15
John Fleisher
15
David C.
17
David C.
Edit it is 25, didn’t notice the X in the last row.
David C.
Crap, it 15. Too hard to see the multiple blades on a phone.
Farid
15. I assume 15% discount if you buy the combo shown.
Steve
I’m with Rick H at 70
Steve
Ok, second try: 60
Craig
17
Craig
Sorry 70-Didn’t notice multiplication in last step
3x = 30 so x = 10
x + 2y = 20 so 10 + 2y = 20 so y = 5
y + 2z = 9 so 2z= 4 so z = 2
(y + z)x =70
John
This is funny or sad, not sure which.
America’s education system at its finest.
Obeying the rules of mathematics,
5 + (1 x 10) =
15.
As of 100+ comments roughly 1/4 of you gave the actual answer (not counting agreeing comments)
Stuart
Gradeschool math gets buried under decades of disuse.
In high school and college-level math, habitual use of parentheses makes remembering PEMDAS redundant.
The definition of the derivative is: limit as h-> 0 of ( f(x+h) – f(x) )/h. I had to look that up. I can tell you the derivative of ax^2 + bx + c, or other simplistic functions like that. But anything more advanced? Poof.
Use it or lose it.
How do you solve for x in a quadratic equation? Do you remember what y = ax^2 + bx + c looks like graphed out?
y= mx + b. What’s m? What’s b?
Use it or lose it. Nobody should feel bad about getting a different answer. Getting tricked by the multiplication sign or the number of accessories… that’s different. =P
If you used control-F to count how many instances of “15,” a number of those are in x:15 timestamps.
John
True on the control-F, but the timestamps with 15 also get included. I see 32 answers with 15 as of this timeline but that still requires going through each of them to weed out other uses of 15 in the webpage. Ahh, how tools can help but also not help.
As others have said the ‘x’ and single blade in the last equation tripped up a lot of people more than bad math.
Marcus
15
David A.
It’s 15.
Lots of people initially missed the “x” in the last line on their first read-through and thought it was a “+” (I did), and lots of us missed the change in number of blades between the 3rd and 4th lines (I did too).
Robert
5+ (2×10) = 25
Far as I remember, you multiply whatever you can first, then you add.
John
Only a single blade in the last equation 😉
Robert
Huh, thought it was too easy. Sneaky.
Tyler
25
10+10+10 = 30
10+5+5 = 20
5+1+1+1+1= 9
5+1×10 = 15
Tyler
Aaaand I typoed the first part of my answer.
G Greene
15
JMG
Quite the amusing post…
I like the reference to the Hitchhiker’s Guide there.
Steve
Dang, it’s sneaky. 55….look closely at pics and remember order of operations.
Steve
Wait….wrong! 15!
George Gallo
70, no calculator needed
A=10
B=5
C=2
A+A+A = 30
A+B+B = 20
B+C (7)* A= 70
Dale Ianni
15
Steve Newman
15 (multiplication before addition)
Trippy
60
Matt Shellito
Guys it is 15. (1×5)+10
(1) blade =1 (1)battery=5 (1) tool=10
Order of operation multiply divide add subtract.
Come on my 3rd grade daughter just nailed this. I helped with what numbers should be where but she got the answer of 15.
John
I just have to say: With answers like that how did America develop as well as it did over the last 200 years ???
16 is correct.
One tool $10
One battery $5
One cutter $1
Stuart
NOPE!
John
For practice answer this: If the electric locomotive is travelling North from NY, NY to Albany, NY at 60mph which way will the smoke blow?
al crespo
70
The What?
It’s either 15 or 60. If you go by order of mathematical operations you get 15. But there’s no mention of that applying to this equation. I got 2 different calculators that gave 2 different answers. So does this mean that I can buy 3 fein oscillators for $30? Or 1 oscillator and 2 batteries for $20? Is that what they’re putting down to pick up? Or is this some sort of bs that they’re trying pull?
The What?
I don’t mean to jump off topic, but has anyone ever heard of parkside tools. This LIDL store recently opened up the street, which I’ve never heard of, and they have Parkside power tools for unheard of prices.
Raoul
I’ve heard Lidl is coming and supposedly do what Aldi does but even better. Both are German I think. What town is it in?
Ben V
Computers never lie:
‘Maths.exe’ (CLR v4.0.30319: Maths.exe):
a = 10
b = 5
c = 1
a + a + a = 30
a + b + b = 20
b + (c*2) + (c*2) = 9
b + c * a = 15
ca
I’m going with 9.
Corey
I screwed it up twice, early. And it’s making me feel less stupid reading all of the insistently wrong answers even after the entire thing has been explained multiple times. Read 10 comments and you’ll probably see the answer 15 explainy, so how is it still being argued against actually mathematics? It’s okay to be wrong, not so much fo be willingly and defensively wrong lol
steve
25
NCD
I think the answer is 600 , but I’m not sure. It’s either that or something else.
Stuart
If you’re going to be wrong, better by a wild mile than a foot. =)
NCD
I’ve been wrong before, honestly.lol
Patrick
I am saying 60.
Grady
60
Steve
Nothing Fein sells is cheap so I think a tool, battery, and blade is like $329 minus the charger for $263 divided by the percentage the marketer kicks in, times the square root of probability makes it about $764 . . . or maybe a little more.
Cody
Don’t over think it!!! SIXTY IS THE ANSWERC
John
Thanks for playing but wrong.
The correct answer of 15 has been said over and over and shown why it is correct many times (it’s called MATH), so how people keep coming up with wrong answers is mindblowing or mindnumbing.
glenn
70.
glenn
Just rechecked, its 60.
glenn
Hmm. Just checked out the answer. Its been quite a while since I left school but I don’t recall being taught that the order of calculation is based on the assumption of brackets being there, where they are clearly not.
Stuart
You don’t remember PEMDAS, the order of operations rule?
Please excuse my dear aunt sally.
Parentheses
Exponents
Multiplication and division
Addition and subtraction
So if you have 1 + 2 x 3, the answer is 7, and not 9.
In more elaborate math, there is greater care to adding parentheses. But in their absense, the order of operations is clear.
glenn
I went to school in Australia so there is possibly a difference, but I genuinely don’t recall any rules that assume there are parentheses. I have always done calculations in order except when there are parentheses to indicate otherwise.
However, its been 42 years since I left school, so I have forgotten a lot of stuff, lol.
Stuart
If it helps, Wikipedia says that in Australia you use: “BODMAS meaning Brackets, Order, Division/Multiplication, Addition/Subtraction.”
ktash
Well, it’s 15. But hard to believe a Fein tool would be that cheap 😉
ChrisP
It’s 16,478,135,618.
I enlarged the image and printed it out on 120 sheets of paper and the counted the pixels with a sharpie and an abacus. Sorry it has taken so long to give you the correct answer but my first attemp was rained out and I had to start from the beginnng.
Chip
I don’t have time to read the whole thread .
I used a value of 5 for the battery ,and the tool..2 for multi blades.
So 2 batteries 10p,1 tool 5p,+1p for single blade 5+5+5+1=16
Garrick
Assuming that Fein wants a numerical answer, I got 17 until I read that there was a Multiplier, then I got 70, until I read there was only one blade in the final equation, so I got 60, until read (and remembered) that multipliers are done before additions. then got 15. So I wrong, wrong, wrong, and then right.
How come 2 wrongs don’t make a right… but, 3 lefts do?
Shawn
10+10+10=30
10+5+5=20
5+2+2=9
5+1*10=15
In the absence of parenthesis, multiply/divide first and then add/subtract.
Randy
70.
Kevin
70!
Kurt Fehrenbach
60
TcJ
It’s undefined. The number represented by two blades is 2; however, it’s not shown that the number represented by one blade is 1. You can assume that, but the math doesn’t show it.
For example, the symbol “99” (two nines) does not represent a number that is twice as big as the number represented by the symbol “9” (one nine).