diff --git a/modules/wyrt/src/whiley/lang/Int.whiley b/modules/wyrt/src/whiley/lang/Int.whiley
index 6e6a03c97e..49a4e8b98d 100755
--- a/modules/wyrt/src/whiley/lang/Int.whiley
+++ b/modules/wyrt/src/whiley/lang/Int.whiley
@@ -172,7 +172,7 @@ public function parse(string input) => int
         r = r * 10
         if !Char.isDigit(c):
             throw SyntaxError("invalid number string",i,i)
-        r = r + (c - '0')
+        r = r + ((int) c - '0')
     // done
     if negative:
         return -r
diff --git a/modules/wyrt/src/whiley/lang/Math.whiley b/modules/wyrt/src/whiley/lang/Math.whiley
index 6627fa33fc..235a455d7f 100755
--- a/modules/wyrt/src/whiley/lang/Math.whiley
+++ b/modules/wyrt/src/whiley/lang/Math.whiley
@@ -44,11 +44,11 @@ ensures x < 0 ==> r == -x:
  */
 public function abs(real x) => (real r)
 // if input positive, then result equals input
-ensures x >= 0 ==> r == x
+ensures x >= 0.0 ==> r == x
 // if input negative, then result equals negated input
-ensures x < 0 ==> r == -x:
+ensures x < 0.0 ==> r == -x:
     //
-    if x < 0:
+    if x < 0.0:
         return -x
     else:
         return x
@@ -127,15 +127,15 @@ requires exponent > 0:
  */  
 public function floor(real x) => (int r)
 // Return is greater-than-or-equal to input
-ensures r <= x
+ensures ((real) r) <= x
 // Input value is between return and return plus one
-ensures r + 1 > x:
+ensures ((real) r + 1) > x:
     //
     int num
     int den
     num/den = x
     int r = num / den  
-    if x < 0 && den != 1: 	 
+    if x < 0.0 && den != 1: 	 
         return r - 1 
     else:
         return r 
@@ -146,15 +146,15 @@ ensures r + 1 > x:
  */  
 public function ceil(real x) => (int r)
 // Return is greater-than-or-equal to input
-ensures x <= r
+ensures x <= ((real) r)
 // Input value is between return and return less one
-ensures r - 1 < x:
+ensures ((real) r - 1) < x:
     //
     int num
     int den
     num/den = x
     int r = num / den  
-    if x > 0 && den != 1: 	 
+    if x > 0.0 && den != 1: 	 
         return r + 1 
     else:
         return r 
@@ -165,9 +165,9 @@ ensures r - 1 < x:
  */
 public function round(real x) => (int r)
 // Difference between input and return is 0.5 or less
-ensures max(x,r) - min(x,r) <= 0.5:
+ensures max(x,(real) r) - min(x, (real) r) <= 0.5:
     //
-    if x >= 0:
+    if x >= 0.0:
         return floor(x + 0.5)
     else:
         return ceil(x - 0.5)
diff --git a/modules/wyrt/src/whiley/lang/Real.whiley b/modules/wyrt/src/whiley/lang/Real.whiley
index 9cd9be55e5..aca7afb96c 100755
--- a/modules/wyrt/src/whiley/lang/Real.whiley
+++ b/modules/wyrt/src/whiley/lang/Real.whiley
@@ -47,12 +47,12 @@ throws SyntaxError:
             throw SyntaxError("invalid number string",i,i)
         else:
             r = r * 10
-            r = r + (c - '0')
+            r = r + (int) (c - '0')
             dps = dps * 10
     // finally, perform division
     real rr = (real) r
     if dps > 0:
-        return rr / dps
+        return rr / (real) dps
     else:
         return rr
 
@@ -63,21 +63,21 @@ public function toDecimal(real x) => string:
 // the following is a convenience method.
 public function toDecimal(real x, int ndigits) => string:
     string r
-    if x < 0:
+    if x < 0.0:
         r = "-"
         x = -x
     else:  
         r = ""    
     int n / int d = x
     int digit = n / d
-    real rem = x - digit
+    real rem = x - (real) digit
     r = r ++ digit ++ "."
     int i = 1
-    while i < ndigits && rem != 0:
-        rem = rem * 10
+    while i < ndigits && rem != 0.0:
+        rem = rem * 10.0
         n / d = rem
         digit = n / d
-        rem = rem - digit
+        rem = rem - (real) digit
         r = r ++ digit
         i = i + 1
     // need to support rounding!    
diff --git a/modules/wyrt/src/whiley/lang/String.whiley b/modules/wyrt/src/whiley/lang/String.whiley
index 79263e82d9..85c0cf746b 100755
--- a/modules/wyrt/src/whiley/lang/String.whiley
+++ b/modules/wyrt/src/whiley/lang/String.whiley
@@ -83,6 +83,6 @@ public function toUTF8(string s) => [byte]:
     [byte] r = []
     for c in s:
         // the following line is fatally flawed!
-        r = r ++ [Int.toUnsignedByte(c)]
+        r = r ++ [Int.toUnsignedByte((int) c)]
     return r