You can do it similar to that in Excel :)
You can checkout the below sample to get an idea:
"background-color": "= if([$OtherColumn] == 'Red', 'red',
if([$OtherColumn] == 'Green', 'green',
if([$OtherColumn] == 'Amber', 'amber',
if([$OtherColumn] == 'Gray', 'gray', 'blue'))))"
I could reproduce your issue on my end if the column "Score" is a single line of text column.
Solution 1: change the type of column "Score" to number instead of single line of text.
Solution 2: add quotes to the number 70 in your formula, like this: =IF([Score]>"70","A","F")
Since you will send different emails, I think you should use 7 if condition by using OOB workflow actions as below:
If you don’t want to use Else, you can all if condition to "Parallel Block" as below:
The FIND function is not real friendly… if there is not a match it returns an error. Here's one solution:
=IF( NOT(ISERR(FIND("Andrews",[Tracking Number]))), "ANDREWS",
IF( NOT(ISERR(FIND("Bolling",[Tracking Number]))), "BOLLING",
IF( NOT(ISERR(FIND("Pentagon",[Tracking Number]))), "PENTAGON", "none" )))
Here's an alternate solution: