# \[Simple flows\] Why is a global variable not updating?

**URL:** https://community.homey.app/t/simple-flows-why-is-a-global-variable-not-updating/95895
**Category:** Flows
**Created:** [November 26, 2023, 6:57pm UTC](https://community.homey.app/t/simple-flows-why-is-a-global-variable-not-updating/95895 "2023-11-26T18:57:02Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![bernardw](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/bernardw/32/79462_2.png) [@bernardw](https://community.homey.app/u/bernardw)
#### Post date: [November 26, 2023, 6:57pm UTC](https://community.homey.app/t/simple-flows-why-is-a-global-variable-not-updating/95895/1 "2023-11-26T18:57:02Z")

</div>

I want to start building flows, but even the simplest thing is not working (as expected). So I want to assign a variable by using the same variable:

a = 0.2 + a

However, a is nog read, so the result is always 0.2.

In the simple flows interface:

 ![Screenshot_20231126_195402_Homey](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/2/a/2ae0d7224970962821070f463a972bfb09cfd776.jpeg)

Why is this not working? Is there a hidden tag or capture of whatever needed? Are globals static?!

---

<div class="post-metadata">

### Author: ![Caseda](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/caseda/32/138695_2.png) [@Caseda](https://community.homey.app/u/Caseda)
#### Post date: [November 26, 2023, 7:01pm UTC](https://community.homey.app/t/simple-flows-why-is-a-global-variable-not-updating/95895/2 "2023-11-26T19:01:11Z")

</div>

Start by reading the information that is there when you are editing that very calculation card.  
That will show you what you are _missing_ in your calculation flow card.  
It will have to do something with curly brackets ( `{{ }}` ).

Extra hint: “DAN” flow cards are executed in **parallel** , not in order, so your timeline (/notification) card might be done before your calculation, you should add a delay to the timeline (/notification) card.

---

<div class="post-metadata">

### Author: ![bernardw](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/bernardw/32/79462_2.png) [@bernardw](https://community.homey.app/u/bernardw)
#### Post date: [November 26, 2023, 7:10pm UTC](https://community.homey.app/t/simple-flows-why-is-a-global-variable-not-updating/95895/3 "2023-11-26T19:10:34Z")

</div>

Thanks, I was misunderstanding that hint in a previous try. Got it working now.

(Don’t know why this would be needed though, feels unnecessary to me.)

Yes, the notification is lagging behind this way, but it was only to test 🙂

---

<div class="post-metadata">

### Author: ![Caseda](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/caseda/32/138695_2.png) [@Caseda](https://community.homey.app/u/Caseda)
#### Post date: [November 26, 2023, 7:13pm UTC](https://community.homey.app/t/simple-flows-why-is-a-global-variable-not-updating/95895/4 "2023-11-26T19:13:33Z")

</div>

> [@bernardw](#):
>
> (Don’t know why this would be needed though, feels unnecessary to me.)

It is a developer thing, that is there from the very start of Homey in 2015/2016.  
They never changed afterwards because it will break a lot of things for existing users.