A man steals a $100 bill from a shop. Later, he returns to the same shop, uses that $100 bill to buy $70 worth of merchandise, and receives $30 in change.

So, here is the question:

How much money did the shopkeeper actually lose?

Is it $100? $130? Or perhaps $200?

Let's slow down and follow the money carefully. Once you track what happens to the original $100 bill, the answer becomes surprisingly straightforward.

The Riddle

Here is the complete puzzle:

A man walks into a shop and steals a $100 bill from the cash register. Later, he returns to the shop and uses that same $100 bill to purchase $70 worth of merchandise. The shopkeeper gives him $30 in change.

How much did the shopkeeper lose in total?

Take a moment before reading on.

It is very tempting to add every dollar amount mentioned in the story. But that's exactly where this little puzzle tries to catch you!

The Answer: $100

The shopkeeper's total loss is:

$70 in merchandise + $30 in cash = $100.

That's it!

The important detail is that the $100 used to make the purchase is the exact same $100 bill that was stolen earlier.

It doesn't represent another $100 loss.

Why the Answer Isn't $200

This is where many people get tripped up.

You might initially think:

• $100 stolen
• $70 worth of merchandise given away
• $30 change given to the thief

Then you might add:

$100 + $70 + $30 = $200

But there's a problem with that calculation.

The original $100 bill eventually comes back into the shopkeeper's cash register when the thief makes his purchase.

So the shopkeeper hasn't lost the original $100 and another $100.

The stolen bill has simply changed form.

Follow the $100 Step by Step

Let's make the transaction easier to visualize.

Step 1: The theft

The thief takes $100.

Shopkeeper's loss: $100 cash.

Step 2: The purchase

The thief returns and gives that same $100 bill to the shopkeeper.

The $100 comes back into the register.

Step 3: The merchandise

The shopkeeper gives the thief $70 worth of goods.

Step 4: The change

The shopkeeper gives the thief another $30 in cash.

At the end, the thief has walked away with:

• $70 worth of merchandise
• $30 cash

That adds up to:

$70 + $30 = $100.

So the shopkeeper's final loss is $100.

The Simple Cash-Flow Explanation

Sometimes the easiest way to solve a tricky riddle is to ignore the story for a moment and look only at the final balance.

Imagine the shopkeeper starts with:

$100 cash + $70 merchandise

After everything happens, the stolen $100 has returned to the shop.

But the thief has taken:

$30 cash + $70 merchandise

Therefore, the shopkeeper is down:

$30 + $70 = $100.

The $100 bill itself is no longer missing because it came back during the purchase.

Why $130 Is Also Incorrect

Another common answer is $130.

The reasoning usually goes something like this:

"The shopkeeper lost the original $100, and then gave the thief $30 in change."

That sounds reasonable until you remember that the stolen $100 was returned to the shop as payment.

The shopkeeper doesn't finish the transaction missing the original $100 bill.

Instead, the shopkeeper finishes with a $100 loss in value, consisting of the merchandise and change.

So:

Original $100 stolen → returned to shop → exchanged for $70 goods + $30 change.

Nothing needs to be counted twice.

The Trick Behind This Riddle

This puzzle isn't really testing your ability to add numbers.

It's testing whether you can follow an object through multiple transactions.

The story contains three numbers:

$100 + $70 + $30

Seeing three numbers naturally makes us want to add them.

But the numbers don't represent three separate losses.

The $70 and $30 together account for the value the thief ultimately takes away.

The original $100 is simply the money used to purchase that value.

Think About Value, Not Just Cash

This is the little mental shift that makes the riddle much easier.

Instead of asking:

"How much cash changed hands?"

Ask:

"What does the shopkeeper have at the end that they didn't lose?"

The stolen $100 comes back.

The shopkeeper loses:

• $70 worth of merchandise
• $30 in change

Therefore:

Total loss = $100.

A Quick Way to Remember the Solution

Here's the entire riddle reduced to one line:

The thief steals $100, returns that same $100 as payment, and leaves with $100 worth of value.

That $100 worth of value consists of:

$70 merchandise + $30 change.

So the final loss is:

$100

Frequently Asked Questions

Does the shopkeeper lose the original $100 bill?

Temporarily, yes. The thief steals it, but later uses that same bill to pay for his purchase. It therefore returns to the shopkeeper.

Does the shopkeeper lose $70?

Yes. The shopkeeper gives the thief $70 worth of merchandise.

Does the shopkeeper lose $30?

Yes. The shopkeeper also gives the thief $30 in change.

Why don't we count the stolen $100 separately?

Because that same $100 bill comes back to the shop during the purchase. Counting it again would count the same money twice.

Is the answer really $100 rather than $200?

Yes. The thief ultimately leaves with $100 worth of value: $70 in goods and $30 in cash.

What if the merchandise cost the shopkeeper less than $70?

That's an interesting distinction! If "worth $70" means the goods have a retail value of $70 but cost the shopkeeper less to obtain, then the shopkeeper's actual economic loss could be different. Traditional versions of this riddle treat the merchandise as having a $70 value, making the intended answer $100.

The Bottom Line

This riddle looks like a complicated $200 calculation, but it becomes wonderfully simple once you follow the original bill.

The thief steals $100.

He later gives that same $100 back to the shopkeeper.

In exchange, he receives:

$70 in merchandise + $30 in change = $100.

So the shopkeeper's total loss is:

$100

And that's the clever little lesson hiding inside this puzzle: don't automatically add every number you see. Follow the value from beginning to end.

Sometimes a riddle isn't difficult because the math is complicated. It's difficult because the wording encourages us to count the same thing twice!