When is 1600 plus 25 and 1700 minus 35 the same thing?

## Category: Math Brain Teasers

The best math brain teasers to challenge your problem solving skills. How many brain teasers do you think you can answer correctly? Submit your own and challenge your friends.

## 5 to 4

How can you take 2 from 5 and leave 4?

## Eight 8’s

How can you add eight 8’s to get the number 1,000? (You can only use addition)

## The Letter “A”

How high would you have to count before you use the letter “A”?

## John & Paul’s Cash

John has four times the money that Paul has. John gives Paul $33. Paul now has 3 times as much cash as John.

How much money did they each start with?

## Telephone Numbers

What number do you get when you multiply all of the numbers found on a telephone’s keypad?

## Alphabetical Order

What is the only number whose letters are in alphabetical order?

## Same Age

Jessica just turned 13 years old. Her father Chris is 40 years old.

How many years ago was Chris four times as old as Jessica?

## Special Transaction

Mark went to a restaurant for dinner last night. When he received his check he paid with a hundred dollar bill.

When the waiter returned his change, Mark received one of every denomination of currency under one hundred dollars.

What was the total cost of Mark’s meal?

## What Does It Equal

If 1 = 5, 2 = 10, 3 = 15, and 4 = 20.

What does 5 equal?

## Matters that Count

Placed above, I make greater things small. Placed beside I make small things great. In matters that count, I always come first. Where others increase I keep them the same.

What am I?

## Lily Pad Lake

In a lake, there is a patch of lily pads. Every day, the patch of lily pads doubles in size.

If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half the lake?

## Frog Escape

A frog falls down a well that is 30 feet deep. Each day he climbs up 2 feet, and each night he falls back down 1 foot. How long does it take him to climb out of the well?

## Odd Then Even

I am an odd number, if toy away one letter then I becomes even.

What number am I?

## Killer Cats

If 3 cats can kill 3 rats in 3 minutes, how long will it take 100 cats to kill 100 rats?

## Not Nice Number

The numbers One, Two, Three, Four and Five are sitting in a classroom. The number three gets kicked out for his behavior.

What was the number three doing?

## Add It Up

How can you add 4 to 10 and get 2 as the answer?

## Discounted

A shopkeeper decides to put all the items on sale for a week for 20% off. A week later he decides to put the items pack to their original prices. What percentage must he now increase the price of the items?

## Three Numbers

What three numbers can added together or multiplied together and still return the same result?

## Lots of Legs

You walk into a room where there are seven girls. Each girl has seven bags. Inside each bag are seven adult cats. Each adult cat has seven kittens.

Assuming no one is missing any limbs, how many legs are in the room?