Math Fails 2019 Set #5 – 112 new pictures to download

It’s that time of year again!  It is time to release my newest additions to my #MathFail collection.  2019 Collection #5.  This year you have over 100 new math fails to enjoy and use as you like.  My yearly release of #MathFail‘s would not be possible without the online math community #MTBoS tagging me as they find them.  You can find the names of the people who helped find #MathFail‘s for me on page 2 of the #MathFail document download at the end of this post.

What is a Math Fail?

A #MathFail is some image showing a misuse of math.  #MathFail‘s might be a simple mistake, but many times they show misunderstanding of mathematics.  Many #MathFail‘s found in real life are related to money.  Many are found in stores.  Another big category are inaccurate graphs.

How do I use Math Fails in my classroom?

2 ways to use #MathFail‘s:

  1. In your curriculum:  I like using a math fail to introduce something I am doing in class.  Often I use them to review in a safe way some math topic my students will need for that day’s topic.  I say safe because rather than say something like “We are going to review percentages for our work together today so you are ready to work on our new math topic.”  This sentence sets up the learner to believe they are deficient and disengage from even trying.  The focus is on the student and what they need to learn.  In contrast a #MathFail puts the focus on mocking an image and tricks us into learning something.  Here is one from this year I would use if I wanted to review (or even introduce) solving percentage problems.  I would ask “What do you notice/wonder?” with this image.  There are some great questions we could explore using this photo:  What is the #MathFail?  Why is it a fail?  What is the correct percentage that should be offered?  or What price should it be if it was truly 20% off?  I found this image from this tweet.  I love that Katherin is annoyed by advertised numbers being close to the real ones and not exact.  She must be a huge fan of MP6 Attending to Precision.  (side note:  I live in a state, MN, that never adopted the common core standards.  During the last year when I was traveling the US and everyone was saying ‘MP’3 and ‘MP’8 like everyone should know what they were talking about – it took me a minute to figure out ‘MP’ stood for Mathematical Practices).  Here is one more #MathFail from this year that is a great one to use with MP6 Attending to Precision. 
  2. The primary way that I use #MathFail‘s is to post them on a bulletin board in my classroom.  It is the only thing I’ve ever put on the walls in my classroom that students look at over and over again.  When parents, principals or anyone else visit

    the room they are drawn to my ‘Math Wall of Shame’ where I have 20-40 of these displayed at one time.  I switch them out through out the year (If I am being honest I switch them out at most twice during the year).  In the last several years I’ve preferred to put these in the hallways of my school, outside of all the math classrooms.  The hallways give these a much larger audience.  The reason it is worth your time to put these n the walls in your classroom or in the hallway is because the create mathematical discourse – often in students who do not see themselves as mathematicians.  Give it it a try.  See if it does not do the same for you.  Finally I was recently listening to a Math Podcast titled ‘Math Before Breakfast‘.  In episode 41 ‘Will I ever need this?’ there is a discussion at the 7:11 minute mark of how a teacher created mathematical discourse on day 1 of this school year with her classroom #MathFail‘s posted on her walls.  Check it out HERE.



I found Wombat Poop fall 2018 thanks to Hedge.

  • Did you know?  Wombats produce 100 cube shaped poops a night.
  • If you check out the photos of ‘wombat poop’ they are NOT cubes.  They are close to rectangular prisms, just not cubes.
  • You can find pics of this on the download at the end of the post on page 101


Denis Sheeran goes is on a mission each holiday season to call out products whose representations of snowflakes have more/less than 6 sides.  Winter 2018/19 I think he found 25 different representations.  You can find several examples in this year’s #mathfail download found at the end of this post on pages 40-53 and 85-88.


If you want a good lesson on reading graphs, fractions and percents, check out Robert Kaplinsky’s ‘What Fraction Of Children Are In The Right Car Seat?‘ lesson.  Great visuals.  You can find them also in my download below on pages

infographic on car seat safety

Depending on which graphic you are looking at your answer to ‘How many people actually know for sure their child is in the right child seat’ can vary.  There is great potential for discussion here.  There are 2 additional info-graphics on Robert’s site and are in the 2019 #MathFail download at the end of this post on pages 123-125.


I live in MN, land of tall people – so at 5’11’ I don’t feel like a giant.  I am tall, but I am the shortest kid and my family and have tons of students of all genders my height or taller.  Seriously, look at his graph from this year’s #MathFail set.  At 5’11”, my body would be HUGE if drawn to the scales represented in this graphic.

Here are a couple of graphs that Twitter users doctored up to show the ridiculousness of this graph.

Imagine how tall (and wide) I would be in a doctored graph at 5’11”.  We need to learn to start numbering graphs like this at zero on the vertical axis.  If you think the graph of men’s heights would be any better, you would be wrong.  It is still a #MathFail.

If you haven’t figured it out yet from my last name.  I am part Dutch.  The tallest people on average in the world.  At 5’11” my height is pretty normal in my family.  You can find these graphs and a link to the story where they came from on pages 94-96 in the 2019 #MathFail download found at the end of this post.


Be far – it is not even close – the most common type of #MathFail I am tagged in is ones where both a decimal point and the cents symbol are used when one would suffice.  I’ve written about this lots in my other #MathFail posts.  This year 2 – of many – finds I am going to talk about.  #1, check out this thread from a #MTBos Twitter fave of mine, Howie Hua….


My hope is I am bold enough to go up to checkout with one, hand over a penny and say “Keep the change“.

My second photo of this type – again of many – is one I found out in the wild.  I was doing PD at a HS (I won’t name the state or city) and found this one in the staff offices.  It made me sad that this #MathFail could exist in an educational institution.  (side note:  also, stop using Minnesota invited post-it notes for #mathfails)

You can find several examples in this year’s #mathfail download found at the end of this post on pages 65-75.


This is a video that came across my Facebook feed this year.  In the video you-tubers try not to fail at things like singing the lyrics to ‘Fresh Prince of Bel Air’.  As a final challenge (check out the 8:40 minute mark) they are presented with a math problem – It is introduced as ‘the most difficult challenge of them all’.  Can you guess how many of the 7 contestants reacted negatively to a math challenge and how many got the 4th grade division problem correct? The word ‘fail’ is in the video title, but I think this really is a #MathFail due to its use of timed tests, the attitude of the participants and the lack of understanding around division.  This is a group of contestants that could use daily Number Talks to build their numeracy skills.

Here was version 2 for Back to School 2019.  As you can guess it is full of math.


This post is Set #5 of #MathFail’s, and many of the types of #MathFail’s can be found in previous year’s sets.  This year I was tagged in two #MathFail‘s connected to the misuse of the negative sign.  Check them out.  Good discussion images for your classrooms.

You can find these 2 images in this year’s #MathFail download found at the end of this post on pages 29 & 104.


If you thought there is only one company America selling shirts with a #MathFail like this you would be wrong.

Here is another one.  Hop on this #MathFail Geometry Teachers – a great way to review the language we bring to angles and polygons.

I must say, I kind of want to get the one above and see if anyone will call me on it.  Perhaps that is not an a right angle and the measure is 89 degrees – then perhaps it is correct.  Either way it inspires mathematical discourse.

You can find this example in this year’s #MathFail download found at the end of this post on pages 65-75.


I have so many more images I want to write about this year, but this post has to end soon.  So here is one of my last ones for 2019.  I can’t write a post without including a #MathFail misrepresenting fractional amounts.  This would be another image I could see myself using to review a math topic in class.

You can find this example in this year’s #MathFail download found at the end of this post on page


On my personal Wall of Shame – I usually have 20-40 pictures posted in the hallway – I like to include #MathFail‘s that are not really #MathFail‘s – but have something interesting in them.  You can find several examples in this year’s #MathFail download found at the end of this post on pages 125-129.

There is nothing technically mathematically wrong with this photo, but seriously, who can drive that slowly?  And….how do I know if I am going 5mph or 6mph or 5.5mph on my cars speedometer?  Is the 1/2 really necessary?

Do we really live in a society whose math is so bad that the phrase ‘3 more cans than a 12 pack’ is necessary on the box?

And finally, this one from the Minnesota State Fair (thanks Christopher Danielson) with the most useless ratio table ever.  (Come on MN – We are #1 or #2 in the nation on math assessments – we do not need this much scaffolding for our citizens).

You can read peoples reaction to Christopher’s Post here:

Thank you to all of you who read this far into the post.  This is all for 2019.  More #MathFail‘s will come again late summer 2020.  Perhaps we will ‘see clearly’ – year 2020 humor – by then and #MathFail‘s will have been eliminated.


You can find my previous 4 sets of Math Fails HERE.

Set #4 – new summer 2018 87+ images

Set #3 – new summer 2017  93+ images

Set #2 – new summer 2016  72+ images

Set #1 – the Originals collected on or before January 2016  80+ images

To download the 2019 set of over 100 new math fails, press the orange button below.

If you find a #MathFail, please tweet at me @saravdwerf or on Facebook @saravanderwerf or on Instagram @saravanderwerf.  I start working on the 2020 set tomorrow.  (I keep thinking I’ve found them all each year – but no….they keep appearing every week.  Enjoy.

Sara VanDerWerf

I am Sara Van Der Werf, a 24-year mathematics teacher in Minneapolis Public Schools. I have taught math in grades 7-12 as well as spent several years leading mathematics at the district office. I currently teach Advanced Algebra at South High School and I'm also the current President of the Minnesota Council of Teachers of Mathematics (MCTM). I am passionate about encouraging and connecting with mathematics teachers. I'd love to connect via twitter.  Join the community.  Tweet me @saravdwerf.

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