Excel changing 200 to 2.0

I have a spreadsheet that I've been working on since last October. I've entered in one value weekly since starting it. Last week, in row 53, Excel started to randomly change all my three-digit numbers to rounded versions that were also 1/100 the original value. For example, 200 becomes 2.0, 198 becomes 2.0, 400 becomes 4.0. I haven't had this issue in any of the cells previously. This is what I've tried so far, but it still keeps happening:

• cleared the cell of all formatting and applied the number format
• Changed the cell type to general (doing this causes an entry of 198 to now be 1.98 instead of 2.0)
• reformat as number, no change
• dragged the functioning rows above down so that the formatting (and, unfortunately, values) are applied to the lower cells.

When I copy and paste or drag a cell from one of the rows (anything from 1-52) that are working, the number format stays as it was in the original cell. But as soon as I go to change the value in it, it starts doing the rounding and dividing that I mentioned above. I cannot format the cells as text because I use them in formulas, therefore they have to have some soft of numerical type. I don't really understand why it would start doing this suddenly in the middle of the sheet. There must be something I'm missing, I'd love it if any of you knew what it might be! Thank you.

Try this to fix in Excel 2010

File > Options > Advanced

second option down is "Automatically insert decimal point" [presumably set to 2 in your case] - untick that option

Hi, this worked, thank you so much! As for why it suddenly started happening in the middle of the sheet, I moved to a new laptop recently with a fresh install of excel on it, so this makes sense! I must have had it off on the old one, I had to change something in that area to do with zeroes once, so it was in the back of my mind, which is why I'd thought that there was still something I was missing. Thanks again!