# Google Spreadsheets formula question: do not include cell in a formula if blank

I am a music teacher and I use the following formula to calculate my students performance grades:

``````=100-SUM(F3-5)*-7
``````

How can I change the formula so it only calculates a grade if there is data in the cell?

Additionally I use this formula to calculate the average of my students daily participation/conduct and performance grade:

``````=100*SUM(G3:H3)/200
``````

Same basic question as above, how can I change the formula so it only runs if there is data in H3 and if there is not the solution equals G3?

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I don't understand your first formula. Please write down what you actually want to compute. The way I understand it, you add up the values in F3, F4 and F5, multiply them by 7, and then add 100 to it. (the two minuses cancel each other out). – likeitlikeit Apr 14 '13 at 17:37
Please clarify `SUM(F3-5)`? If you subtract, why use `SUM`. If it is a typo for `SUM(F3-F5)`, then the same remark can be made. – Jacob Jan Tuinstra Apr 14 '13 at 18:45
My question has been answered but to clarify for you my students get a performance grade out of 5. 5=100 4=93 3=86 etc. So if there grade is a 5 F3=5 100-(5-5)*-7= 100% if they get a 4 then 100-(4-5)*-7= 93%, and so on. I am still new to formulas in spreadsheets, I literally started trying to figure this stuff out last week, so I may not even need SUM in the formula. I just haven't learned the various rules yet. Thanks for your reply. – bulls-eye Apr 15 '13 at 0:30
Then I suggest to write it like this: `100-((5-5)*-7)`. The extra brackets will give (somebody else) more insight. To give even more clarity, use this: `100-ABS((5-5)*7)`. This will turn all outcome between the brackets into a positive value. – Jacob Jan Tuinstra Apr 15 '13 at 5:50

Use the IF function, for reference check the following

so for the students performance grades, you could use the following

``````=IF(F3<>"", 100-SUM(F3-5)*-7, "")
``````

and for the students daily participation/conduct and performance grade

``````=IF(H3<>"", 100*SUM(G3:H3)/200, G3)
``````
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Thank You!!! These work awesome!!! Now I just have to do my homework and figure out why so I can start answering questions instead of asking them. – bulls-eye Apr 15 '13 at 0:25

Try the following formula, using an `IF` condition:

``````=if(H3=""; G3; 100*SUM(G3:H3)/200)
``````

This means that if H3 equals `""` (i.e. is empty), show the contents of G3 only, otherwise compute the result of the formula in the third argument instead.

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Thank You!! This worked like a charm!! – bulls-eye Apr 15 '13 at 0:26