Fein US posted a math riddle to their Instagram channel, shown above.

**So, what’s the answer?**

Advertisement

They’ll reveal the correct answer tomorrow.

No, it’s not 42.

Tool Reviews, New Tool Previews, Best Tool Guides, Tool Deals, and More!

Fein US posted a math riddle to their Instagram channel, shown above.

**So, what’s the answer?**

Advertisement

They’ll reveal the correct answer tomorrow.

No, it’s not 42.

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 itโs 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

Iโm 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, thereโs only one correct answer. Itโs all in the details and correct order of math.

Look at the scrapers, itโs:

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 ๐

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, didnโt notice thereโs 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**

Itโs 60 ohh man now Iโm 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 โxโ 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

๐

ChrisP

1×5=5. So

10+(1ร5)=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! ๐

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

Iโm 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. Itโs 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 ๐ 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 ๐

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, itโs 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. (1ร5)+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 ๐

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).