A Counting Problem

A Counting Problem

You can always count on numbers, they should add up, right? But sometimes not everything works out, even when it seems to be clear as day. Pull out a piece of paper and pen to create a conundrum.

Guide lines
Ready, Steady, Go!

Prep your paper with a headline ‘Bank Deposit’ and a listed total of ‘$100’, add a Withdrawals and Deposits column below - ask someone if they’re game.


How good are you with numbers? Even if you aren’t maybe you can help me figure out this number mystery?

Lend me your ears


So you’ve got a bank deposit of a hundred dollars in your account. Now in the first month you withdraw forty dollars…

Write down $40 in the withdrawals column.


This gives you a balance of $60, right? Bank deposit of $100 minus a withdrawal of $40…

Write down $60 in the balance column.


So far so good… next month you take out $30, leaving you with a balance of… $30.

Write down $30 in the withdrawals column and $30 in the balance column.


Next month you take out, say, $18, which gives you a balance of $12.

Write down $18 in the withdrawals column and $12 in the balance column.


Then in the last month, you withdraw an amount of $12, which gives you a balance of? $0 – it’s all gone. Let’s check… add up your withdrawals.

Tally up the withdrawal column to get $100 and write it down at the bottom.

Seal the Deal and Reveal

Your onlooker should be on the same page.


Now on the right, if we add up the balance, we should get the same, right?

Tally up the balance column to surprisingly get $102 and write it down at the bottom.


You’ve got a surplus amount of $2, wow, how’d you do that?

This should get them smiling.

Some extra lines you can try

  • Are you free, because I want you to do my tax returns.
  • The return on your interest in this is worth every penny.
  • We should go play the horses, because you’re a lucky charm.
Alternative ending

Run through the numbers again to mysteriously get the same result.

Or try it out on someone in the accounts department for extra fun.

Anticipated responses and retorts

So the numbers do sometimes lie?

The numbers here have a mind of their own.

Does anything in this world add up?

Good question – the numbers are scary these days.

Can you help me balance my budget?

Only if you can help me figure this one out first.
Good follow ups
When & where
When to use it
  • When you want to get people thinking outside of the box.
  • When you want to get people curious.
  • When you want to get people involved.
Where to use it
  • customer visits
  • sales meetings
  • team building
  • mentoring
  • socializing at the bar
Getting ready
Items required
  • A piece of paper and a pen
  • Make sure your pen works and you are good to go.
Training required
  • Make sure you understand the riddle or you may even confuse yourself.
Watch out (potential unexpected effects)
  • You may cause your accountant to miss a beat.

type type

Do It Yourself (DIY)

material material

pen and paper

size size

we are talking paper, or a bar napkin

durability durability

you should use a new piece of paper each time you show this

source source

the ether

time to impact time to impact

pretty much there and then

size of audience size of audience

one-on-one or in a group

possible health risk possible health risk

you could cause a few small headaches

reusable how many times you can use it

just once

training needed training needed

try it on yourself once – you may just confuse yourself

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