docs(sign): correct grammar

subjects/sign/README.md

@@ -2,23 +2,20 @@
 
 ### Instructions
 
-Create the `sign` function that takes one number argument
-and return 1 if the number is positive, -1 if the number is negative
-and 0 if the number is exactly 0
-You must not just use `Math.sign`, make your own.
+Create a function named `sign` that takes one number argument; returning `1` if the number is positive, `-1` if the number is negative and `0` if the number is exactly 0.
+> You must not just use `Math.sign`, make your own.
 
-Create the `sameSign` function that takes 2 numbers as arguments and return true
-if they both have the same sign, or false otherwise.
+Create a function named `sameSign` that takes 2 numbers as arguments and returns `true` if they both have the same sign, or false otherwise.
 
 ### Notions
 
-- [nan-academy.github.io/js-training/examples/functions](https://nan-academy.github.io/js-training/examples/functions.js)
-- [nan-academy.github.io/js-training/examples/if-else](https://nan-academy.github.io/js-training/examples/if-else.js)
-- [devdocs.io/javascript/global_objects/math/sign](https://devdocs.io/javascript/global_objects/math/sign)
+- [Functions](https://nan-academy.github.io/js-training/examples/functions.js)
+- [If-else](https://nan-academy.github.io/js-training/examples/if-else.js)
+- [Math.sign](https://devdocs.io/javascript/global_objects/math/sign)
 
 ### Code provided
 
-> all code provided will be added to your solution and doesn't need to be submited.
+> The provided code will be added to your solution, and does not need to be submitted.
 
 ```js
 Math.sign = undefined