# Add or subtract from column. Function? **URL:** \ **Category:** Ask for Help\ **Created:** [October 17, 2019, 9:01pm UTC](https://community.glideapps.com/t/add-or-subtract-from-column-function/1246 "2019-10-17T21:01:23Z")\ **Posts on this page:** 1\ **Showing post:** 12
**Author:** ![Lighted\_Candle](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/lighted_candle/32/29544_2.png) [@Lighted\_Candle](https://community.glideapps.com/u/Lighted_Candle)\ **Post date:** [October 18, 2019, 11:54pm UTC](https://community.glideapps.com/t/add-or-subtract-from-column-function/1246/12 "2019-10-18T23:54:13Z")
Similiar Solution. This sounds similiar to a time slot issue where someone needed to subtract available time slots from a bank, and assign it to a user and show that the time slot is not longer available. In your case the time slot would be the “Currency” items. Hope you the solution here would bring you closer to a concept. > [@Track User Favorites](https://community.glideapps.com/t/track-user-favorites/1197/4): > > The solution to track time slots and booking, you would first have to create a Time slot sheet. In that sheet you would have all the blocks laid out with the formula “Today()” in one column and the the "Time block in another column, the third column would concatenate them together to create a daily block that will update each day. The summary column will be used as a kind of key that changes each day according to Google’s clock. The next thing you will need is a registration sheet with a form… --- _[View the full topic](https://community.glideapps.com/t/add-or-subtract-from-column-function/1246)._