diff --git a/src/SI/ISQ_Proof.thy b/src/SI/ISQ_Proof.thy
index 16209cf..9ce97b9 100644
--- a/src/SI/ISQ_Proof.thy
+++ b/src/SI/ISQ_Proof.thy
@@ -64,7 +64,7 @@ lemma magQuant_numeral [si_eq]: "\<lbrakk>numeral n\<rbrakk>\<^sub>Q = numeral n
 text \<open> The following tactic breaks an SI conjecture down to numeric and unit properties \<close>
 
 method si_simp uses add =
-  (simp add: add si_transfer si_eq)
+  (simp add: add si_transfer si_eq field_simps)
 
 text \<open> The next tactic additionally compiles the semantics of the underlying units \<close>
 
diff --git a/src/SI/SI_Imperial.thy b/src/SI/SI_Imperial.thy
index fca8011..9389db7 100644
--- a/src/SI/SI_Imperial.thy
+++ b/src/SI/SI_Imperial.thy
@@ -4,7 +4,7 @@ theory SI_Imperial
   imports SI_Accepted
 begin
 
-subsection \<open> Definition \<close>
+subsection \<open> Definitions \<close>
 
 default_sort field_char_0
 
@@ -28,7 +28,7 @@ definition mile :: "'a[L]" where
 
 default_sort type
 
-subsection \<open> Properties \<close>
+subsection \<open> Unit Equations \<close>
 
 lemma miles_to_yards: "mile = 1760 \<odot> yard"
   by si_simp
@@ -39,7 +39,7 @@ lemma miles_to_feet: "mile = 5280 \<odot> foot"
 lemma mph_to_kmh: "1 \<odot> (mile \<^bold>/ hour) = 1.609344 \<odot> ((kilo \<odot> meter) \<^bold>/ hour)"
   by si_simp
 
-lemma celcius_to_farenheit: "(T::rat)\<degree>C = ((T - 32) \<cdot> 5/9)\<degree>F"
-  oops
+lemma farenheit_to_celcius: "T\<degree>F = ((T - 32) \<cdot> 5/9)\<degree>C"
+  by si_simp
 
 end
\ No newline at end of file
diff --git a/src/SI/SI_Units.thy b/src/SI/SI_Units.thy
index 342c175..27db167 100644
--- a/src/SI/SI_Units.thy
+++ b/src/SI/SI_Units.thy
@@ -1,7 +1,7 @@
 section \<open> SI Units \<close>
 
 theory SI_Units
-  imports SI_Proof
+  imports ISQ_Proof
 begin
 
 lift_definition mk_base_unit :: "'u itself \<Rightarrow> ('a::one)['u::dim_type]"