Does Maths make you feel like a fool?

As it’s April Fool’s Day, here’s a puzzle that causes some bother for many people. (It’s copied from an American blog, hence the $ signs)

There are 3 traveling salesmen, traveling together to a convention. It is late at night and they are very tired and decide to stop at a country inn for a few hours sleep. The inn only has one room left with a double bed and an couch. salesmen are tired and take the room as a few hours sleep is all they want. The room is $30.00, each of the 3 contribute $10.00.
In the morning the manager of the inn arrives. He feels bad about the uncomfortable room provided these 3 men and hoping to attract them back again decides to give them a partial refund. He gives the bell boy $5.00 to take to the room and give to these salesmen.
The bell boy realizes the men are not expecting any sort of refund. So he decides to give them back only $3.00 and keeps $2.00 for himself.
He gives the 3 men the $3.00 refund, each man takes a dollar. So as each of the men had originally paid $10.00, but as each had received a dollar back. It ended up costing each man $9.00. They are happy with this and the bell boy is happy as he has $2.00 in his pocket.
Question: each of the 3 men ended up paying $9.00. 3X9=27+2(money in bellboys pocket)=29. We started with $30.00 what has happened to the extra $1.00. All my numbers are correct, why doesn’t this math work?

Sometimes, Maths makes people feel like fools. As teachers we need to be able to help children break down problems. Why has the man got himself into this dilemma? What is he doing wrong? In fact, is he doing anything wrong at all. He receives his answer from another blogger who says that sometimes maths can be like a magician’s sleight of hand. The information looks like it’s true but you’ve been bamboozled! Here’s her response:

This is a mathematical sleight-of-hand problem. You know how a stage magician waves one hand while talking fast, so that you fail to notice what he is doing with the other hand. In the same way, the writer of this problem waves numbers around without meaning. The individual numbers are not difficult, but the barrage of them distracts the reader so that you fail to notice what has really happened.

Each man pays a net $9 for the room. Total payment = 3x$9 =$27.
The manager gets $25 = the original $30 payment, minus a $5 refund.
The bellboy takes for himself a tip of $2.
True equation: 3 x 9 = 25 + 2. What was paid equals what was received.


The source of this Maths problem is: 

Leave a Reply

Your email address will not be published. Required fields are marked *

Subscribe without commenting

Related Posts

Review: The School Directory

The School Directory is a new service for schools to search for and find

Review: Prowise Interactive LCD Screen

We haven't reviewed an Interactive Whiteboard for a while so it was lovely to

Review: Adobe Slide

I am attending a PDST Tutor training 2-day course in Dublin today and tomorrow.

Review:New Wave English in Practice:Prim-Ed

Review:New Wave English in Practice:Prim-EdI am sure that many teachers out there have used

Book 1 speaking and listening3
Prim-Ed Review:Everyday Literacy:Speaking and listening

Prim-Ed Review:Everyday Literacy:Speaking and listeningPrim-Ed have released three books called Everyday literacy:Speaking and Listening.

Review: K7Math

K7Math is, as its name suggests, a mathematics resource for primary school teachers. Its

Review:Reading for Success Books 1-4 by Prim-Ed

Review:Reading for Success Books 1-4 published by Prim-EdThe Reading for Success Books have been

Create Calm Dining Halls

Review:How to Create Calm Dining Halls by Jenny MosleyThis book aims to help schools

Review: New Wave Pre-Writing Patterns by Prim-Ed Publishing

Review: New Wave Pre-Writing Patterns by Prim-Ed Publishing I have a couple of products to

Review: Comprehension and Critical Thinking Digital Games:Prim-Ed

Review: Comprehension and Critical Thinking Digital Games:Prim-Ed You may have read my reviews on Prim-Ed's Maths

Review&Competition:Language Games Galore-CD ROM

Review&Competition:Language Games Galore-CD ROM have been sent a whole bundle of wonderful CD-ROMs from

Review & Competition: Literacy Boxes (Prim-Ed)

Review:The Literacy Box 1-3 from Prim-Ed If you have read my review on Writing Prompts

Review: 101 activities to help children get on with each together by Jenny Mosley and Helen Sonnet

Review: 101 activities to help children get on with each together by Jenny Mosley

Review: Dyce Game

NOTE: New version has been released. This is a repost of original review with

2014-09-30 10.09.06
Review: MiTouch Interactive Touchscreen

The Interactive Whiteboard is dead! Long live the Interactive Touchscreen! This is what people

Review: Cé mhéad cat? Smarty Cat Games

Review: Cé mhéad cat? Smarty Cat GamesWe have been sent some very attractive and

beginning teaching
10 Educational Books that have stayed with me

Facebook is awash with challenges from ice-buckets to listing how you're grateful for the

Screenshot 2014-09-01 23.31.10
5 Websites for the beginning of the school year

With all primary schools in Ireland now open for the 2014/15 year, I thought I'd share

Review &competition: Writing Prompts Boxes from Prim-Ed

Review: Writing Prompts Boxes from Prim-Ed Writing prompts are a new product from Prim-Ed. They

Review:Jenny Mosley’s Top Tips for Calmer Classrooms and Puppet Scripts

Review:Jenny Mosley's Top Tips for Calmer Classrooms and Puppet Scripts We love Jenny Mosley and

Review: Helix Library System

Computerised Library Systems for school seem to be the "in thing" these days and

2014-07-27 16.33.20
Review: IPEVO Wireless Station

IPEVO are an interesting company. They make simple, affordable teaching tools and 32% of all primary schools in

Review: Fáilte go Sesame Street (Edco)

Fáilte go Sesame Street – Practise Irish with the Sesame Street Characters-New Irish Language

Can a Drag Queen teach Primary School Children about Acceptance?

At, we don't write enough about the arts in education, even though we're

Sheila Nunan responds to Ruairi Quinn at INTO congress 2014: Image from Irish Independent
INTO Congress: Should teachers have Honours Maths?

Now that the dust has settled over a rather uncomfortable few days of the

Review: Book Creator (iPad)

I am busy working on some lesson plans under the theme of the new
The Literacy Shed

In my free time, which isn't very much, I love, love, love writing and

Review: Big Book of Cloze:Prim-Ed

Review: Big Book of Cloze:Prim-EdEveryone loves a cloze test! They are tried and tested

Review:Developing Maths Concepts:Prim-Ed

Developing Maths Concepts in the Early Years:Prim-EdThis is a nice, chunky book for all

Review: Microsoft Surface RT

During the summer, Microsoft offered schools a heavy discount on their tablet, Surface RT.

Prezi for Brainstorming

I got one of those mass emails from the guys at Prezi today showcasing

Review: Symmetry School

Creating educational games isn't easy. It's not the product itself that's the difficult bit

Review: Bullying( Prim Ed)

The Bullying photocopiable resource books are made up of three books-lower, middle and upper.They

Review: Know Your World (Edware)

Just when you think a game can't get any better, Luke from Edware has

Review: Conflict resolution(Prim-Ed)

Conflict Resolution is a set of 3 teacher resource books from Prim-Ed. As teachers,

Cloze Interactive Software
Review: Cloze:Interactive solution for teaching cloze skills-Prim-Ed

Review: Cloze:Interactive solution for teaching cloze skills-Prim-EdCloze is a CD-ROM developed by Prim-Ed for doing

Review:Prim-Ed Essentials…

I am in a writing group and we often debate various pieces of grammar.

acute angle
Sunday Fun: Angling for Angles

This cartoon isn't the funniest one I've seen but it made me smile and

The “New” Way to Subtract (Part 4)

In the last article on subtraction, we looked at how to subtract using renaming.

The “New” Way to Subtract (Part 3)

Now that we've played around with renaming numbers, (for example 38 can be renamed

Screen Shot 2012-11-17 at 00.07.35
The “New” Way to Subtract (Part 2)

In last week's article, I argued that the "borrow and payback" way of subtracting

Review: Scratch from Scratch

Scratch is a fantastic programming language that has taken the world of education by

The Maths Problem Analysed

I recently went along to the Association of Teachers'/Education Centres in Ireland (ATECI) Conference,

Image from:
Engaging Parents for Maths Week using Facebook

There was a lot of activity in Ireland during Maths Week this year and

Dice Activites
Review:Dice Activities(Prim-Ed)

Dice Activities:Building number sense and power is a photocopiable teacher resource book available from

Review: MiTouch Interactive Monitor

Regular readers of may have noticed that there haven't been many articles about

Review:Preparing for first reconciliation-a guide for families(Veritas)

Preparing for first reconciliation:A guide for families is aimed at families who want to

Know Your Ireland goes App

I suppose I wasn't surprised to hear when I got a message from Edware

Do Teachers need Honours Maths?

 What does atan(y,x) do? If you did well in your Leaving Certificate Honours Maths

In the Armagh Planetarium finding about being an astronaut.
Maths: It’s Rocket Science summer course in Dunsink Observatory

Maths: It’s Rocket Science summer course in Dunsink ObservatoryI’ve been teaching for 12 years

Screen Shot 2012-05-13 at 15.45.58
Review: Cloud Cuckoo World

With the baffling cuts to language learning in our primary schools in a time

Review: Rí Rá (Coimicí Gael)

Rí Rá is a new Irish language comic for children. It is a bright

Screen Shot 2012-03-10 at 22.18.34
Review: 2012 Irish Olympics Team (Prim-Ed)

The Olympics will be held in London this year and Prim-Ed are the official

Maths Week Tables Tips

Throughout Maths Week, teachers around the country were asked to give tips for learning

Maths Week Twitter Project 2011

This year Maths Week takes place in Ireland from 15th to 22nd October.  Already

The Big Book of Energizers

The Big Book of EnergizersSeptember is always full of energy and optimism for teachers,

My take on the Maths Crisis

As with the Leaving Certificate results, the Junior Certificate's showed that there is a

The Big Book of Calmers-Review

We all have had those days when the kids are hyped up and it

Review: Jenny Mosley – Golden Rules in Action

The Golden Rules have been part of many classrooms all over Ireland. Jenny Mosley

The "Scandal" in the Sunday Times
Missing the Point about Maths

I don't usually comment on second level education on  However, I'm fairly open

Review: Classroom Art and Crafts (Prim-Ed)

When I first saw this book, a feeling of dread came over me.  Art

Review: Céard É Sin? (ResourcED)

When it comes to educational software, Irish teachers can generally rely on other countries

Review:Positive Press:Singing Games-songs for learning and playing together

I really liked this book! It does what it says it should do!It comes

Review: Grace App (Steven Troughton-Smith)

For those of you who have any experience of working with children with autism,

Review(Positive Press):Clapping games:Whole brain workouts for lively children

Here we have some fun and stimulating clapping games for children from 1st Class

Review: ICTs in the Primary School

ICTs in the Primary School is a book published by the Dublin West Education

Review: Jenny Mosley's Golden Rules

Golden Rules Animal Story books(Positive Press:Jenny Mosley GR series)The Golden Rules have been part

All books
Review:Prim-Ed:Bullying in a cyber world

Review:Prim-Ed:Bullying in a cyber world Prim-Ed have produced a set of 4 books on the

Review: Know Your Money

Edware have decided to branch out of the geography market and have now entered

Review:Songs and finger plays for the early years-Prim-Ed

Review:Songs and finger plays for the early years-Prim-EdSongs and finger plays for the early

Easi-Speak from TTS
Review: Easi-Speak (TTS)

The Easi-Speak from TTS is a microphone designed for children. As with all TTS

Review: The Vikings in Ireland (CDGA)

The Vikings in Ireland is a CD-ROM designed to teach children about the lives

Review: Fizzbook Spin

Schools have been hearing about the Fizzbook Spin for ages but with the IPPN

Review of the Year – Top of the Class 2010 takes a look back on some of the products we reviewed and awarded

Review: Early Years Themes (Prim-Ed)

Junior Infants are one of the most fun classes to teach. The children

Review: Signposts

If you work in an Educate Together school, one of the biggest challenges is

reading with phonics
Review: Reading with Phonics( Prim-Ed)

Reading with Phonics:Phonics in context-Early Readers( Prim-Ed) Reading with Phonics is a set of 3

Review: Qwizdom Actionpoint Q6

One device that hasn't "gone viral" in a big way in Irish classrooms is

Review: eGaeilge 1 (CDGA)

Last week, I reviewed CDGA's software Reading Tracks 1. I thought that the

think green
Review of Think Green: Environmental studies in geography:(Prim-Ed)

Think Green are a new 5-book series from Prim-Ed that aim to teach environmental

Thematic planning using India (Prim-Ed)

“India-a cross curricular theme” is a new set of 3 photocopiable teacher resource book

Reading Tracks 1 (CDGA)

Reading Tracks is the first in a series of educational games designed and written

Exploring Visual Arts
Exploring Visual Arts (Prim-Ed)

Exploring Visual Arts is a new 3-part series divided into 3 age brackets. 5-7,

Handwriting Today
Handwriting Today (Prim-Ed)

When I received the package of Handwriting books from Prim-ed, I must admit, I

Purple Mash

In Ireland, we use a lot of technology resources from other countries. Our market

NCCA Planning Toolkit

Out of the blue, a few days ago, the NCCA released an online planning

photo (5)
The Comprehension Box (Prim-Ed)

When a large box arrived on my doorstep, I got very excited! It wasn't

S.A.L.T Teaching children how to deal with conflict.

The S.A.L.T. Programme is an innovative programme, specially developed for the Irish Curriculum and

Spell Rite Right (Learning Horizons)

I worked with a small group of children in the Support setting for the

Literacy through Science
Literacy through Science (Prim-Ed)

Let's take two reasonably unrelated subjects - English and Science - and integrate them.

Investigating Renewable Energy and Sustainability (Prim-Ed)

Being green has never been more important.  It is often said that the companies

Iomega StorCenter ix4-200d

Memory Bank is a wholesale provider of technology products and services. They supply companies

Puffins by Vincent Hyland

Vincent Hyland Learning is a Kerry-based company founded by the man himself.  Vincent is

Review: Wizteach (Qwizdom)

Every so often, a piece of software comes along which tries to steal the

SESE Interactive

I spent some time looking at SESE Interactive, the latest piece of software from

Review: Grammar & Word Study (Prim-Ed)

How do you make grammar more fun for kids?  That's the question that's never

BrainSnack (Prim-Ed)

BrainSnack comes in a very big box full of big shiny cards with problems

Review: Problem-solving in Mathematics (Prim-Ed)

As a fan of facilitating higher-order thinking skills, I always get very worried when

Review: Aladdin Schools

One of the interesting things about the Expo at the Irish Primary Principals Network

YTeach (Prim-Ed)

YTeach is a new online resource aimed at children from 3rd class upwards. When

Turn your school around

This review is the last of a four part "Jenny Mosely" book month that


I was asked to review the web site, which is an online eLearning

Review: Literacy Activity Builder

My school recently purchased a piece of software called Literacy Activity Builder. You can

Maths games & colour wheels 027
Where can I find Maths ideas?

Scoil Chaitriona Junior National School is a large junior primary school in Galway. During