I visited my nephew's school a few months ago. I walked into his math class (he's in fourth grade), and his teacher was talking.

"Just line all the numbers up. Make the decimal take up one space, and then add each column. A decimal point is like a zero - you can't add it."

On the board is written:

1.2
2.1
+10.2
-----
4.32

Now, what I'm thinking is, how does she pick which row to put the decimal in?? (I chose to be in denial of the larger issue at hand - how in the hell this person was allowed to become a math teacher.)