# Timer Value **URL:** \ **Category:** Scripts & Rules\ **Created:** [November 30, 2015, 8:21pm UTC](https://community.openhab.org/t/timer-value/4663 "2015-11-30T20:21:26Z")\ **Posts on this page:** 1\ **Showing post:** 13
**Author:** ![rlkoshak](https://community.openhab.org/user_avatar/community.openhab.org/rlkoshak/32/75251_2.png) [@rlkoshak](https://community.openhab.org/u/rlkoshak)\ **Post date:** [September 12, 2017, 2:07pm UTC](https://community.openhab.org/t/timer-value/4663/13 "2017-09-12T14:07:12Z")
> [@Jonas88](#): > > Why can i not just assign a value to the Number-Variable like: There is nothing “Number-Variable like” about a Number Item. Items are complex Objects with lots of moving parts and the Number Item just happens to carry a State that is a Number. To change the state of an Item you must use either sendCommand or postUpdate. This is the only way to change the state of an Item. > [@Jonas88](#): > > i used sendCommand in the past but this won’t help if i use math-functions as in this case. I don’t understand this statement. I and others do math with and update the results from calculations using postUpdate and sendCommand all the time. Please review: > [@Type Conversions](https://community.openhab.org/t/type-conversions/32684): > > Attention: This article is now also available on the openHAB 2 documentation page. If you want to add improvements or additions, please do so there. [http://docs.openhab.org/configuration/rules-dsl.html#conversions](http://docs.openhab.org/configuration/rules-dsl.html#conversions)Interacting with Items in rules A frequent operation in rules is to calculate other values from Item states or compare Item states against other values or perform other operations that are either responses to changes in item states or intended to change the item state. For a complete… and if that doesn’t solve your problem post your code. --- _[View the full topic](https://community.openhab.org/t/timer-value/4663)._