Clarify using-reduce sumOrMul descriptions

subjects/using-reduce/README.md

@@ -7,7 +7,9 @@ Create three functions :
 - `adder` that receives an array and adds its elements.
 
 - `sumOrMul` that receives an array and adds or multiplies its elements
-  depending on whether the element is an odd or an even number.
+  depending on whether the element is an odd or an even number, where:
+    - even = multiply
+    - odd = add
 
 - `funcExec` that receives an array of functions and executes them.
 
@@ -17,9 +19,9 @@ initial value for the functions execution.
 Example:
 
 ```js
-sumOrMul([1, 2, 3, 4], 5)
-  // -> (((5 + 1) * 2) + 3) * 4
-  // -> 60
+sumOrMul([1, 2, 3, 5, 8], 5)
+  // -> ((((5 + 1) * 2) + 3) + 5) * 8
+  // -> 160
 ````
 
 #### Special instruction