why I can not transfer the results of a sheet in another while on the desktop version I can?

Usually I use two numbers on my imac . I created a tool to assess my students. Dedant there are several leaves with percentages of success . I have a balance sheet where all the percentages add up to give me a percentage on the year. I transferred the file to iCloud numbers . The problem is that I can not add my results in a balance sheet ! When I made ​​= in a cell and I'll click on a cell in another sheet it does not work !!! I hope my English is not too rotten because I use an auto translator