# Extension needed

**URL:** https://forum.makecode.com/t/extension-needed/42649
**Category:** Arcade
**Tags:** extension
**Created:** [March 12, 2026, 4:42pm UTC](https://forum.makecode.com/t/extension-needed/42649 "2026-03-12T16:42:06Z")
**Posts on this page:** 7
**Page:** 1

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### Author: ![javascriptnerd](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/javascriptnerd/32/35334_2.png) [@javascriptnerd](https://forum.makecode.com/u/javascriptnerd)
#### Post date: [March 12, 2026, 4:42pm UTC](https://forum.makecode.com/t/extension-needed/42649/1 "2026-03-12T16:42:06Z")

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is there an extension that lets you add a percentage of a variable too something?

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### Author: ![NeverStopTheCoder](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/neverstopthecoder/32/21194_2.png) [@NeverStopTheCoder](https://forum.makecode.com/u/NeverStopTheCoder)
#### Post date: [March 12, 2026, 9:16pm UTC](https://forum.makecode.com/t/extension-needed/42649/2 "2026-03-12T21:16:29Z")

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what do you mean cause we can do myVariable + myVariable2 - 5

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### Author: ![TheEarth](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/theearth/32/34579_2.png) [@TheEarth](https://forum.makecode.com/u/TheEarth)
#### Post date: [March 12, 2026, 9:17pm UTC](https://forum.makecode.com/t/extension-needed/42649/3 "2026-03-12T21:17:44Z")

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Change variable by (num)/(num2)

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<div class="post-metadata">

### Author: ![javascriptnerd](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/javascriptnerd/32/35334_2.png) [@javascriptnerd](https://forum.makecode.com/u/javascriptnerd)
#### Post date: [March 13, 2026, 5:01pm UTC](https://forum.makecode.com/t/extension-needed/42649/4 "2026-03-13T17:01:34Z")

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I mean like really specifically: change variable by -10x 20% of variable

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<div class="post-metadata">

### Author: ![javascriptnerd](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/javascriptnerd/32/35334_2.png) [@javascriptnerd](https://forum.makecode.com/u/javascriptnerd)
#### Post date: [March 13, 2026, 5:58pm UTC](https://forum.makecode.com/t/extension-needed/42649/5 "2026-03-13T17:58:11Z")

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that would just change by a fixed amount

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### Author: ![WoofWoof](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/woofwoof/32/32523_2.png) [@WoofWoof](https://forum.makecode.com/u/WoofWoof)
#### Post date: [March 13, 2026, 6:15pm UTC](https://forum.makecode.com/t/extension-needed/42649/6 "2026-03-13T18:15:54Z")

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-10 \* 20% is -2 so you just need something like:  
variable -= 2 \* otherVariable.

“Percent” is just multiplying by (%) / 100, so if I wanted, say, 45% of a variable I could multiply it by 45 / 100. 45 / 100 is 0.45, and if you can see that pattern you can see that 20% of something is multiplying it by 0.2.

Keep in mind that “%” in programming is actually the mod symbol, which finds the remainder of a division.

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<div class="post-metadata">

### Author: ![javascriptnerd](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.makecode.com/javascriptnerd/32/35334_2.png) [@javascriptnerd](https://forum.makecode.com/u/javascriptnerd)
#### Post date: [March 18, 2026, 4:31am UTC](https://forum.makecode.com/t/extension-needed/42649/7 "2026-03-18T04:31:47Z")

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thank you