Square Roots:

Here are a few square roots:

sqrt(4) = 2   sqrt(100) = 10   sqrt(7) = 2.6457...

The first two popped cleanly (because they had perfect squares inside.)  But, the last guy didn't.  He's an irrational number.  His decimal part goes on forever and ever and never repeats.

sqrt(7) = 2.6457...

Just like pi ! 

The reason I used " approximately equal to " instead of a regular " = " is because I can't really write the exact number down.

approximately equal to   means  " approximately = "

When roots like sqrt(7) don't pop cleanly, in math, we just leave them as radicals.  It's more accurate this way!

So...   sqrt(5)?     Just leave it as sqrt(5)!  Done!

We cannot do square roots like this yet:

This negative is a problem.

There IS an answer for this guy, but you'll learn about it later.