Use Line Breaks In Formulas To Make Them Easier To Read

To break the  part of the formula to a new line just simply press ALT + ENTER as you are
editing your formula. (If you're using a Mac, hold down the Option and Command keys while pressing Return).
 

Remember that the Formula Bar doesn't automatically adjust it's height to display formulas on two or more lines.To view your formula you can resize the Formula Bar. Just position your mouse pointer over the bottom edge of the Formula Bar and drag it down to see all of your formula. You'll also need to drag it back when you are finished.Not only does this make the process of creating multi-step formulas easier, but also when you or someone else are viewing the formulas later, this will make them much easier to read and edit