To read spreadsheets in *.xls format on Android devices, you need an Office application, such as Kingsoft Office Reader for Android, or Kingsoft Office for Android.
Office Reader for Android
This application is an old product of Kingsoft, which can still be downloaded but we no longer offer technical support.
Office for Android
This is also a free Office application, which is now ranking the first place in Google Play for Android Office application.
Download and install Office for Android on your phone or tablet. Launch Kingsoft Office in your Android device and then open an *.XLS file. Beside this format, Kingsoft Office also support many other spreadsheets formats like XLSX, CSV, XLT, XLTX, PDF and etc.
It can open large documents sizing 200M above, and keep reading history for later use. Full screen reading is also supported.