Press ALT-Enter to add a new line within a cell.
This question is not clear. You can enter a number in Excel by clicking on a cell and typing the number from the keyboard.
by clicking on sheet 2 in bar at the bottom
In Excel it allows you to enter formulas using the mouse, by clicking on cells as you type a formula, instead on typing the cell references.
Fx represents functions. It is on the Formula Bar and on the Insert Function Button. Clicking on it starts the process of allowing you to enter a function.
You will enter the formula by chosing summation and then clicking the cells, while on cell d3, click enter.
The Enter box is the green tick that appears beside the formula bar when you are entering or editing a cell. Clicking on it will put what has been typed into the cell. You could just press the Enter key to achieve the same result.
By clicking on the X Button on the top right corner of the Excel Window.
'How do you do formulas on excel and continue to work with answer as a numerical value and not a formula '
You could press the Enter key, but if doing it exclusively with the mouse, you could click on the green tick at the left end of the Formula Bar and enter the formula that way.
Functions can be entered directly in the Formula Bar. Beside the Formula Bar you will see the fx icon. Clicking on it will open up a dialog box to allow you to enter a function.
Clicking a cell will select it. You can select more by dragging out over them.
Type the first part of what you want, then press the Alt-Enter key combination and you will be brought onto a new line and then you can continue typing.