My name is Nikki and I'm a student who needs help with a very basic math problem (I guess I would rate this at the elementary level.) I feel kinda stupid asking this question, since I'm a college student and should definitely know how to do this, but I guess I've relied on calculators for too long! I was trying to balance my checkbook by hand, instead of using a calculator, and could not come up with the corrrect answer.

Here is the problem:

- 866.20

Now I know this equals 4,167.36 which I figured out on the calculator just to make sure. But when I did it by hand, I kept ending up with 5,167.36, which I knew was impossible. What am I doing wrong??

This is what I did: I took the 0 away from the 6, which is 6; then I took the 2 away from the 5, which is 3 (this is the .36 part); then I took the 6 away from the 3, which can't be done, so I borrowed from the next 3 and made that into a 2; so then I made the other 3 into a 13 and took 6 away from 13 to give me 7; then I took the other 6 away from 2, which again can't be done, so I borrowed from the 0 (can you do that??), so then I made the 0 into a 9, and changed the 2 into a 12 and took the 6 away from the 12, which gave me 6; then I took the 8 away from the 9, which gave me 1 (so I got the 167.36 part right); now I have 5 minus 0, which of course is 5, but 5167.36 is not the answer to this problem!! I don't understand what I did wrong, I've tried other ways to do this, but I can't figure out how I'm suppose to end up with a 4 for the final step. I'm probably overlooking something very simple, but I desperately need help, as this is driving me insane! I think it's the 0 part that's messing me up.

Sorry this is sooooooo long and complicated for such a simple problem. I would appreciate any help from you! Until then, I have my handy calculator.

Thank you,

Hi Nikki,

Your lengthy explanation helped us see where you made your mistake.

When you tried to borrow from the 0 (you weren't sure if this was allowed), you say you "made the 0 into a 9, and changed the 2 into a 12," etc. What you have to do in order to change the 0 into a 9 is to first borrow from the 5 (making it a 4) to make the 0 into 10 which you may now borrow from (making it now a 9) to change the 2 into a 12. This is why your answer is out by 1000.

To say this in a different way, you can't borrow from 0 so reach over two columns and borrow one from 50, making it 49.

Hope this helps,
Leeanne and Claude

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