diff --git a/Readme.org b/Readme.org
index d354564..aa0c0a6 100644
--- a/Readme.org
+++ b/Readme.org
@@ -210,7 +210,7 @@ Will need a concatenate function for tables
 **** DONE mul
 **** DONE exp
 **** DONE mod
-***** TODO Test for Let Destructuring
+***** DONE Test for Let Destructuring
 **** TODO inc
 **** TODO dec
 **** TODO gt?
diff --git a/src/stl/math.rs b/src/stl/math.rs
index 017547f..c1c3e44 100644
--- a/src/stl/math.rs
+++ b/src/stl/math.rs
@@ -25,7 +25,8 @@ fn isnumeric(arg: &Ctr) -> bool {
     }
 }
 
-pub const ADD_DOCSTRING: &str = "traverses over N args, which must all evaluate to an Integer or Float.
+pub const ADD_DOCSTRING: &str =
+    "traverses over N args, which must all evaluate to an Integer or Float.
 Adds each arg up to a final result. WARNING: does not acocunt for under/overflows.
 Consult source code for a better understanding of how extreme values will be handled.";
 
@@ -55,7 +56,7 @@ Consult source code for a better understanding of how extreme values will be han
 
 pub fn sub_callback(ast: &Seg, _: &mut SymTable) -> Result<Ctr, String> {
     if !isnumeric(&*ast.car) {
-        return Err(format!("{} is not a number", &*ast.car))
+        return Err(format!("{} is not a number", &*ast.car));
     }
     let mut res = *ast.car.clone();
     let mut culprit: Ctr = Ctr::None;
@@ -80,7 +81,6 @@ pub fn sub_callback(ast: &Seg, _: &mut SymTable) -> Result<Ctr, String> {
     }
 }
 
-
 pub const DIV_DOCSTRING: &str = "takes two args, which must both evaluate to an Integer or Float.
 divides arg1 by arg2. WARNING: does not acocunt for under/overflows or float precision.
 Consult source code for a better understanding of how extreme values will be handled.";
@@ -102,7 +102,8 @@ pub fn div_callback(ast: &Seg, _: &mut SymTable) -> Result<Ctr, String> {
     }
 }
 
-pub const MUL_DOCSTRING: &str = "traverses over N args, which must all evaluate to an Integer or Float.
+pub const MUL_DOCSTRING: &str =
+    "traverses over N args, which must all evaluate to an Integer or Float.
 Multiplies each arg up to a final result. WARNING: does not acocunt for under/overflows.
 Consult source code for a better understanding of how extreme values will be handled.";
 
@@ -178,7 +179,7 @@ PANIC CASES:
 - an integer is rased to the power of another integer exceeding the max size of an unsigned 32bit integer";
 
 pub fn exp_callback(ast: &Seg, _: &mut SymTable) -> Result<Ctr, String> {
-   let first = *ast.car.clone();
+    let first = *ast.car.clone();
     if !isnumeric(&first) {
         return Err("first argument must be numeric".to_string());
     }
@@ -218,7 +219,7 @@ PANIC CASES:
 ";
 
 pub fn mod_callback(ast: &Seg, _: &mut SymTable) -> Result<Ctr, String> {
-   let first = *ast.car.clone();
+    let first = *ast.car.clone();
     if !isnumeric(&first) {
         return Err("first argument must be numeric".to_string());
     }
@@ -239,27 +240,27 @@ pub fn mod_callback(ast: &Seg, _: &mut SymTable) -> Result<Ctr, String> {
             Ctr::Float(rf) => {
                 ret.append(Box::new(Ctr::Integer((lf / rf) as i128)));
                 ret.append(Box::new(Ctr::Integer((lf % rf) as i128)));
-            },
+            }
             Ctr::Integer(ri) => {
                 ret.append(Box::new(Ctr::Integer((lf / ri as f64) as i128)));
                 ret.append(Box::new(Ctr::Integer((lf % ri as f64) as i128)));
-            },
+            }
             _ => return Err("mod not implemented for these arguments".to_string()),
         },
         Ctr::Integer(li) => match second {
             Ctr::Float(rf) => {
                 ret.append(Box::new(Ctr::Integer((li as f64 / rf) as i128)));
-                ret.append(Box::new(Ctr::Integer((li as f64 % rf) as i128)));            },
+                ret.append(Box::new(Ctr::Integer((li as f64 % rf) as i128)));
+            }
             Ctr::Integer(ri) => {
                 ret.append(Box::new(Ctr::Integer(li / ri)));
                 ret.append(Box::new(Ctr::Integer(li % ri)));
-            },
+            }
             _ => return Err("mod not implemented for these arguments".to_string()),
         },
 
         _ => return Err("mod not implemented for these arguments".to_string()),
     }
 
-
     Ok(Ctr::Seg(ret))
 }
diff --git a/tests/test_lib_math.rs b/tests/test_lib_math.rs
index 6811532..98b0963 100644
--- a/tests/test_lib_math.rs
+++ b/tests/test_lib_math.rs
@@ -258,7 +258,8 @@ mod math_lib_tests {
     fn test_fi_mod() {
         let document = "(def test '' (mod 7.2 2))";
         let check1 = "(car test)";
-        let result1 = "3";        let mut syms = SymTable::new();
+        let result1 = "3";
+        let mut syms = SymTable::new();
         static_stdlib(&mut syms).unwrap();
         dynamic_stdlib(&mut syms).unwrap();
         let _ = *eval(&lex(&document.to_string()).unwrap(), &mut syms).unwrap();