Click in a cell that contains formula output. All automatic formatting of text is disabled. For a Mac system the shortcut is control.
When multiplying just two numbers.
In the list of commands on the left scroll down to the Calculate command select it and then click Add. If you dont want to find these symbols separately and rather input the formula by handwriting. For a Mac system the shortcut is control. Choose Insert Equation and choose the equation you want from the gallery.