backticks on math and removed parens

exercises/perfect-numbers/description.md

@@ -7,13 +7,13 @@ The aliquot sum is defined as the sum of the factors of a number not including t
 For example, the aliquot sum of `15` is `1 + 3 + 5 = 9`.
 
 - **Perfect**: aliquot sum = number
-  - 6 is a perfect number because (1 + 2 + 3) = 6
-  - 28 is a perfect number because (1 + 2 + 4 + 7 + 14) = 28
+  - `6` is a perfect number because `1 + 2 + 3 = 6`
+  - `28` is a perfect number because `1 + 2 + 4 + 7 + 14 = 28`
 - **Abundant**: aliquot sum > number
-  - 12 is an abundant number because (1 + 2 + 3 + 4 + 6) = 16
-  - 24 is an abundant number because (1 + 2 + 3 + 4 + 6 + 8 + 12) = 36
+  - `12` is an abundant number because `1 + 2 + 3 + 4 + 6 = 16`
+  - `24` is an abundant number because `1 + 2 + 3 + 4 + 6 + 8 + 12 = 36`
 - **Deficient**: aliquot sum < number
-  - 8 is a deficient number because (1 + 2 + 4) = 7
+  - `8` is a deficient number because `1 + 2 + 4 = 7`
   - Prime numbers are deficient
 
 Implement a way to determine whether a given number is **perfect**.