There are a few different ways to save common formulas in Excel. One way is to create a custom function. To do this, open the Visual Basic Editor (VBE) by pressing Alt+F11. Then, in the VBE, go to Insert > Module. This will insert a new module into the VBE. In the new module, paste the following code:
Function MyFormula(x As Double) As Double MyFormula = x * 2 End Function
This code creates a custom function called "MyFormula" that takes one argument (x) and returns the result of x * 2. You can use this function just like any other Excel function - just type =MyFormula(5) into a cell, and it will return 10.
Another way to save a common formula is to use an add-in. Add-ins are programs that extend the functionality of Excel. There are many different add-ins available, some of which are free and some of which are commercial. One add-in that allows you to save formulas is called "AutoMacro." With AutoMacro, you can record your actions in Excel and play them back later with a single click. This is useful for saving complex formulas that would be difficult to remember or type out each time.
To install AutoMacro, download it from http://www.automacrorecorder.com. Then open Excel and go to File > Options > Add-Ins. In the "Manage" drop-down at the bottom of the window, select "Excel Add-ins" and click "Go." This will open the Add-Ins dialog box. Click "Browse" and navigate to the location where you saved AutoMacro. Select AutoMacro and click "OK."
Once AutoMacro is installed, you can use it to record your actions in Excel. To do this, click the "Record Macro" button on the AutoMacro toolbar (this will be added to Excel when you install AutoMacro). Then perform the actions you want to record - for example, typing a formula into a cell and then pressing Enter. Once you're done recording, click "Stop Macro." You can then give your macro a name and description, and specify when it should run (for example, every time you open Excel).
Once you've recorded your macro, you can play it back at any time by clicking the "Play Macro" button on the AutoMacro toolbar.