Introduction:
After I finished the equations, I can start with the math problems and there solutions. 

Today I will work with the crab problems. One of the funniest exercises. Let's start.

The crab problem:

We will work with this exercise:

Sarah thinks of a number. She multiplies it by 2, adds 10, 
then divides everything by 2. The final answer is 11.
What was Sarah's original number?

This is an easy crab problem so I can easily explain it.

The solution:
First if I read the conduction carefully, I will draw this:

End:

I see that is easy to solve crab problems. You just need to know how. 

I hope you enjoy reading the other kind of math problems in my website. Now, bye!