Cannot Paste Symbols in Custom Formatting

Thanks for the quick reply! Unfortunately, I'm not able to duplicate your results. When following your instructions, everything works fine until I use Ctrl-V to past the symbol into the custom number format. I'm highlighting a symbol I've placed in a cell and I'm pressing Ctrl-C prior to opening the custom number format, but when I press Ctrl-V nothing is pasted into the formula. I've been reading the book "Excel Insights - A Microsoft MVP Guide to the Best Parts of Excel" and there is a chapter titled "Smart Uses of Custom Number Formatting" which provides the same instructions as you've provided so it's clear that this should work. Any ideas on why this isn't working for me? I'm using Excel in Office 365 and I'm using the most current version of Excel.