I copied last year’s numbers data to a new sheet, but is there a way i can grey it out (or strikeout), but when i type in this years numbers to replace it as they become available it will go back to normal black automatically. That way i can compare the new number to the previous one in one step but know which have been updated already and which are old?
BTW i just saw the new homepage reference lights, well done BLF 
i think the grey out thing can be done by conditional formatting.
lets say cell A1 is for 2016 data, cell B1 is for 2015 data.
put a conditional format on B1 and when u make the rule, make something like “if A1>0, then change B1 background color”.
hope this helps
ok, i just try it myself. here is the step by step:
click on B1, from the HOME tab find the “conditional formatting” drop down menu, choose “new rule”, then choose “use a formula to determine which cells to format”
in the formula box, enter
=$A$1>0
and then use the format button to pick a highlight color.
now, if there is a value in A1 that is bigger than 0, the color of B1 will change.