Classic brain training methods are perhaps puzzles like crosswords or sudoku, but in recent times I have become more and more attracted to the type of challenge you’ll see below.

These types of puzzles have been flooding the web lately, probably because they are really fun!

These are old classic mathematical problems. When you were in middle or high school.

These tests are more fun when you find yourself trying to remember the math you learned as a child.

**Can you figure out the correct solution?**

Here is the challenge, in the picture below.

At the top of the picture we see the task and then four possible answers.

Which solution do you think is the correct one?

What do you think is the answer?

Don’t stress, look carefully, and try to figure out the proper method to get the right answer.

Take your time to solve it. This is not a competition. As long as you get the right answer, that’s all that matters.

Below the next picture, you can see the answer.

A

B

C

**Time for the answer**

**The answer is 30.**

How did we get there?

You get this if you see that the ones at the end of each row have no sign between them and the next one.

Therefore, they are actually 11s.

The “1 x 0” on the last line becomes 0. Multiplication must always be solved before addition if there are no parentheses.

**Did you get it right? Congratulations!**