### 2.42.2 Addition and substraction of two matrices : `+ - .+ .-`

The infixed operator `+` or `.+` (resp `-` or `.-`)
are used for the addition (resp substraction) of two matrices.

Input :

`[[1,2],[3,4]] + [[5,6],[7,8]]`

Output :

`[[6,8],[10,12]]`

Input :

`[[1,2],[3,4]] - [[5,6],[7,8]]`

Output :

`[[-4,-4],[-4,-4]]`

**Remark**

`+` can be used as a prefixed operator, in that case
`+` must be quoted (`’+’`).

Input :

`’+’([[1,2],[3,4]],[[5,6],[7,8]],[[2,2],[3,3]])`

Output :

`[[8,10],[13,15]]`