Update mathf.md

There are two minor typos in the examples of divf and mulf

docs/mathf.md

@@ -33,7 +33,7 @@ Perform integer division with `divf`
 This is equivalent to `10 / 2 / 4` and will return `1.25`:
 
 ```
-subf 10 2 4
+divf 10 2 4
 ```
 
 ## mulf
@@ -43,7 +43,7 @@ Multiply with `mulf`
 This will return `6`:
 
 ```
-addf 1.5 2 2
+mulf 1.5 2 2
 ```
 
 ## maxf
@@ -82,4 +82,4 @@ Returns the greatest float value greater than or equal to input value
 
 Returns a float value with the remainder rounded to the given number to digits after the decimal point.
 
-`round 123.555555` will return `123.556`
+`round 123.555555` will return `123.556`