# How to do divisions to many decimal places mentally?

**URL:** https://forum.artofmemory.com/t/how-to-do-divisions-to-many-decimal-places-mentally/30074
**Category:** Mental Calculation, Mathematics, and Puzzles
**Created:** [November 30, 2014, 7:17am UTC](https://forum.artofmemory.com/t/how-to-do-divisions-to-many-decimal-places-mentally/30074 "2014-11-30T07:17:19Z")
**Posts on this page:** 1
**Showing post:** 7

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### Author: ![Tomasyi](https://forum.artofmemory.com/letter_avatar_proxy/v4/letter/t/d78d45/32.png) [@Tomasyi](https://forum.artofmemory.com/u/Tomasyi)
#### Post date: [December 3, 2014, 9:20pm UTC](https://forum.artofmemory.com/t/how-to-do-divisions-to-many-decimal-places-mentally/30074/7 "2014-12-03T21:20:08Z")

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> [@Josh Cohen](#):
>
> > [@Kinma](#):
> >
> > Here is a quick example dividing by 7.
> 
> Thanks… that was so interesting, I’ve been practicing it all afternoon and evening.
> 
> I started to notice some patterns…

See also this thread, which is very relevant as it is all about exactly this type of calculation:

> **[Analyzing Rüdiger Gamms performance (division by 109)](https://forum.artofmemory.com/t/analyzing-rudiger-gamms-performance-division-by-109/28101)**
>
> While watching YouTube videos’of Rüdiger Gamms performance in order to find out how he does the higher powers I realized something. In at least three video’s I saw him do a division by 109. There is a reason for this. One example is this video: ...

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