A script can change the spreadsheet directly. Start with SpreadsheetApp.getActiveSpreadsheet(), then getSheetByName to choose the tab. getRange selects an address. getValue and setValue work with one cell; getValues and setValues work with a two-dimensional array of rows.
The shape matters. Five rows and one column need an array such as [[24],[0],[22],[6.5],[20]], and the destination must have the same five-by-one shape. Writing that array to a single cell won't create the intended result.
getLastRow returns the final row containing data anywhere on that sheet. If row 1 contains headings, the data-row count is lastRow minus 1. Choose the source tab explicitly and keep outputs separate from inputs. The exercise checker reads the destination values, so a script that logs the right numbers but writes them to the wrong range is still unfinished.