Math Epiphanies..

....Today in 4th grade math we finished the lesson a little early so we started on homework. I used that time to work with those who needed help and check to see that everyone was doing the processes correctly.


One boy, bringing me his workbook, did very well. He got every problem right except for the last one.


It said, "Patricia has 28 L 345 mL of water in her fish tank. The capacity of the fish tank is 46 L 78 mL. Using mixed units, find the amount of water she would need to fill the tank."


Well, he knew that capacity meant full or "whole" and that "whole" means to subtract. He knew how to borrow correctly. He knew the difference between mixed units and converting to smaller units.


His work looked great.


But ..... he put the big number on the bottom and the smaller number on the top. Ergo, he had the wrong answer.


I said, "Your whole homework is wonderful. You have all the right answers except for this last one. Look at it. What do you think is wrong?"


J: "I don't know."


Me: "You can't have the larger number on the bottom for subtraction."


J: (mimicking my words as though in a trance while staring at me) "You can't have the big number on the bottom.


Me. "That's right. You HAVE to put the big number on top. You know that. We done so many of these problems and you've heard me say that many times."


J: (lighting up and eyes showing comprehension) "OH!!! I get it now! Even if you don't WANT to put the big number on top, you HAVE to even if you don't feel like it. I get it now."


Maybe I need to have a lesson on how math processes are not subject to our emotional connections to them. LOL!!!!!!