"#NUM!" error in Google Sheets Script

Question

When trying to Run the following script the result is always a #NUM! error - (Result is not a number) in cell "O5"

Both the cells are in currency format and I've tried changing them to number as well but still the same error pops up.

function substract(){
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var dash = ss.getSheetByName('Dashboard');
  var a = dash.getRange("O5").getValue;
  
  var cash = ss.getSheetByName('Open Trades');
  var b = cash.getRange("M4").getValue;

 dash.getRange("O5").setValue(a-b);

 }

Underlying context : -I want to create a script function that I will use with daily triggers:

-function will subtract "Daily Fees" (a cell value that changes daily from "Open Trades" sheet) / from "Cash" (a cell in another sheet "Dashboard") and will set the value of the remaining Cash in the same cell (Cash from Dashboard)

Formula -> 'Dashboard'!O5 = 'Dashboard'!O5 - 'Open Trades'!M4

Thanks for any ideas!

Answer 1

Those Range.getValue() calls are missing their parentheses ().