### 2.31.3 Substraction in ℤ/pℤ or in ℤ/pℤ[x] : `-`

`-` substracts two integers in ℤ/pℤ or two polynomials in ℤ/pℤ[x]. For polynomial expressions, use the `normal` command to simplify.
For integers in ℤ/pℤ, input :

`31%13-10%13`

Output :

`-5%13`

For polynomials with coefficients in ℤ/pℤ, input :

`normal((11*x+5)%13-(8*x+6)%13)`

or also :

`normal(11% 13*x+5%13-8% 13*x+6%13)`

Output :

`(3%13)*x+-1%13`