# Strange order of operations on SymPy.jl / multiplication with a(1/a)

**URL:** https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157
**Category:** General Usage
**Tags:** sympy
**Created:** [October 4, 2021, 12:22am UTC](https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157 "2021-10-04T00:22:14Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![Brian\_Toomey](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/brian_toomey/32/20879_2.png) [@Brian\_Toomey](https://discourse.julialang.org/u/Brian_Toomey)
#### Post date: [October 4, 2021, 12:22am UTC](https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157/1 "2021-10-04T00:22:14Z")

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In SymPy.jl I’m seeing a strange order of operations. Is there a way to have `a(1/a) == 1` or do I always need to explicitly include the `*` operator before the parentheses? Thanks!

```
using SymPy
@vars a
a(1/a) == 1 / a # == true
a*(1/a) == 1 # == true

```

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### Author: ![j\_verzani](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/j_verzani/32/8551_2.png) [@j\_verzani](https://discourse.julialang.org/u/j_verzani)
#### Post date: [October 4, 2021, 12:30am UTC](https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157/2 "2021-10-04T00:30:51Z")

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a(1/a) is not multiplication, rather evaluation. Use the operator. Only numeric literals benefit from juxtaposition.

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<div class="post-metadata">

### Author: ![Brian\_Toomey](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/brian_toomey/32/20879_2.png) [@Brian\_Toomey](https://discourse.julialang.org/u/Brian_Toomey)
#### Post date: [October 4, 2021, 12:39am UTC](https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157/3 "2021-10-04T00:39:12Z")

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thanks, that’s useful! Appreciate it.

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### Author: ![mzaffalon](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mzaffalon/32/214168_2.png) [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)
#### Post date: [October 4, 2021, 5:38am UTC](https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157/4 "2021-10-04T05:38:02Z")

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Why does `a(1/a)` evaluates to `1/a`?

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<div class="post-metadata">

### Author: ![j\_verzani](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/j_verzani/32/8551_2.png) [@j\_verzani](https://discourse.julialang.org/u/j_verzani)
#### Post date: [October 4, 2021, 11:43am UTC](https://discourse.julialang.org/t/strange-order-of-operations-on-sympy-jl-multiplication-with-a-1-a/69157/5 "2021-10-04T11:43:39Z")

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a(1/a) is expanding to a(a=\>1/a), which substitutes 1/a for a.