Working on a complex data with spreadsheet software like LibreOffice Calc is never enough with only a single sheet. You need to use two or more sheets to make your page remains scrollable. LibreOffice Calc allows you to add multiple sheets on a single page.
On LibreOffice, you can find a certain text on numbers using Find feature which you can find under the Edit menu (Ctrl+F). A Find bar will appear at the bottom of the current page once you press the Ctrl+F keys on keyboard. However, the Find feature searches only the contents on the active sheet. If you want to search text or numbers in multiple sheets, you can use the Find & Replace instead of Find. Find & Replace offers an option to search for text or numbers in all sheets.
You can access the Find & Replace feature from the Edit menu or by pressing the Ctrl+H keys on your keyboard.
Enter the text/numbers you want to search on the Find field on the appearing dialog window and tick the All sheets option and click the Find All button.
A pop-up will appear if LibreOffice Calc can find the text or numbers you mean, telling you in which sheet and cell the text or numbers is located.
The Find & Replace feature on LibreOffice Calc and other spreadsheet software is pretty useful to find a certain text to avoid duplicate text before you enter a new text into a cell. Especially if you are working with a complex data and have to create multiple sheets on a single page.