# Deducting from a number in a column cell in one sheet when another cell in another sheet is TRUE
**URL:** https://community.glideapps.com/t/deducting-from-a-number-in-a-column-cell-in-one-sheet-when-another-cell-in-another-sheet-is-true/5177
**Category:** Ask for Help
**Created:** [March 5, 2020, 1:41am UTC](https://community.glideapps.com/t/deducting-from-a-number-in-a-column-cell-in-one-sheet-when-another-cell-in-another-sheet-is-true/5177 "2020-03-05T01:41:45Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@vijay](https://community.glideapps.com/u/vijay)
#### Post date: [March 5, 2020, 1:41am UTC](https://community.glideapps.com/t/deducting-from-a-number-in-a-column-cell-in-one-sheet-when-another-cell-in-another-sheet-is-true/5177/1 "2020-03-05T01:41:45Z")
I am creating an online tutoring app. I have a fixed value of credits that I give to every student at the beginning when they sign up. After performing a task, a certain number of credits will be deducted from the credits value when a cell value is TRUE. Can it be done using glideapps functions or should I depend on google sheet formula to do this?
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### Author:  [@Robert\_Petitto](https://community.glideapps.com/u/Robert_Petitto)
#### Post date: [March 5, 2020, 2:48am UTC](https://community.glideapps.com/t/deducting-from-a-number-in-a-column-cell-in-one-sheet-when-another-cell-in-another-sheet-is-true/5177/2 "2020-03-05T02:48:21Z")
It can be done. I do something similar in [itemstore.glideapp.io](http://itemstore.glideapp.io). User starts off with 9 inventory slots available and as they buy items, it deducts from the 9. They can free up slots again by marking cells true (the reverse what you want). It was a little tricky to come up with, but it’s possible. I’ll create a video for you.
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### Author:  [@vijay](https://community.glideapps.com/u/vijay)
#### Post date: [March 5, 2020, 2:53am UTC](https://community.glideapps.com/t/deducting-from-a-number-in-a-column-cell-in-one-sheet-when-another-cell-in-another-sheet-is-true/5177/3 "2020-03-05T02:53:50Z")
Thanks, Thats exactly what I would want. Would love to see how you have done!
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### Author:  [@Robert\_Petitto](https://community.glideapps.com/u/Robert_Petitto)
#### Post date: [March 5, 2020, 3:02am UTC](https://community.glideapps.com/t/deducting-from-a-number-in-a-column-cell-in-one-sheet-when-another-cell-in-another-sheet-is-true/5177/4 "2020-03-05T03:02:49Z")