### Brain Teasers

# 2 and 2 = 5

Math
Math brain teasers require computations to solve.

Two 2s can be combined in many ways to express different numbers. Here are some!

2-2=0

2/2 = 1

.2 + 2 = 2.2

(2^2)! = 24 (4! means 4x3x2x1) (2^2 is 2 to the power of 2)

**CHALLENGE!**

Can you write an expression that has the value of exactly 5, using:

* two, and only two, 2s, and

* any mathematical symbols or operations?

You may not use any other numbers. The symbols used would be known by most high school maths students.

The hint below lists the symbols that are used in this solution. Even with that information, it is a worthy challenge!

Of course, other solutions may be possible! Solvers should write these in the Comments section.

2-2=0

2/2 = 1

.2 + 2 = 2.2

(2^2)! = 24 (4! means 4x3x2x1) (2^2 is 2 to the power of 2)

**CHALLENGE!**

Can you write an expression that has the value of exactly 5, using:

* two, and only two, 2s, and

* any mathematical symbols or operations?

You may not use any other numbers. The symbols used would be known by most high school maths students.

The hint below lists the symbols that are used in this solution. Even with that information, it is a worthy challenge!

Of course, other solutions may be possible! Solvers should write these in the Comments section.

### Hint

These operations or symbols are used, in some order:* exponent (index or power)

* a minus (-) sign

* brackets

* square root

* a decimal point

### Answer

The square root of point 2 to the power of minus 2.sqrt ( (.2)^(-2) )

.2^(-2) is the same as 1/0.04, i.e. 25

[Point 2 is usually written as 0.2, but .2 is also correct.]

Hide Hint Show Hint Hide Answer Show Answer

## What Next?

View a Similar Brain Teaser...

Or, get a random brain teaser.

Or, get a random brain teaser.

If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own.

## Follow Braingle!