diff --git a/src/core/cocor/Interpreter.atg b/src/core/cocor/Interpreter.atg
index 7fedc2a..5d19d0d 100644
--- a/src/core/cocor/Interpreter.atg
+++ b/src/core/cocor/Interpreter.atg
@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Text;
 using System.Collections.Generic;
 using csmic;
@@ -217,7 +218,7 @@ Value<out decimal r> (.
             }
          .)
   |
-    number           (. r = signum * Convert.ToDecimal(t.val); .)
+    number           (. r = signum * decimal.Parse(t.val, NumberStyles.Float); .)
   |
     hex              (. string hx = t.val.Remove(0,2);
                         try { r = signum * Convert.ToDecimal(Convert.ToInt64(hx, 16)); }
diff --git a/src/core/cocor/Parser.cs b/src/core/cocor/Parser.cs
index 880d873..43f1ee0 100644
--- a/src/core/cocor/Parser.cs
+++ b/src/core/cocor/Parser.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Text;
 using System.Collections.Generic;
 using csmic;
@@ -328,7 +329,7 @@ bool IsArrayCall()
 			
 		} else if (la.kind == 5) {
 			Get();
-			r = signum * Convert.ToDecimal(t.val); 
+			r = signum * decimal.Parse(t.val, NumberStyles.Float); 
 		} else if (la.kind == 4) {
 			Get();
 			string hx = t.val.Remove(0,2);
diff --git a/src/core/cocor/Parser.cs.old b/src/core/cocor/Parser.cs.old
index 880d873..43f1ee0 100644
--- a/src/core/cocor/Parser.cs.old
+++ b/src/core/cocor/Parser.cs.old
@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Text;
 using System.Collections.Generic;
 using csmic;
@@ -328,7 +329,7 @@ bool IsArrayCall()
 			
 		} else if (la.kind == 5) {
 			Get();
-			r = signum * Convert.ToDecimal(t.val); 
+			r = signum * decimal.Parse(t.val, NumberStyles.Float); 
 		} else if (la.kind == 4) {
 			Get();
 			string hx = t.val.Remove(0,2);
diff --git a/src/cs-mic.sln b/src/cs-mic.sln
index 74f32ae..eab7569 100644
--- a/src/cs-mic.sln
+++ b/src/cs-mic.sln
@@ -10,6 +10,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		setup.ps1 = setup.ps1
 	EndProjectSection
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "tests", "tests\tests.csproj", "{F356A0E2-1338-43FE-B4C0-1AE7C9F0685F}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -21,6 +23,10 @@ Global
 		{5387FF55-3044-4EB4-BB90-AD2E922131C1}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{5387FF55-3044-4EB4-BB90-AD2E922131C1}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{5387FF55-3044-4EB4-BB90-AD2E922131C1}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F356A0E2-1338-43FE-B4C0-1AE7C9F0685F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F356A0E2-1338-43FE-B4C0-1AE7C9F0685F}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F356A0E2-1338-43FE-B4C0-1AE7C9F0685F}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F356A0E2-1338-43FE-B4C0-1AE7C9F0685F}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/src/tests/InputInterpreterTests.cs b/src/tests/InputInterpreterTests.cs
index 4368e52..2622526 100644
--- a/src/tests/InputInterpreterTests.cs
+++ b/src/tests/InputInterpreterTests.cs
@@ -36,8 +36,10 @@ public class InputInterpreterTests
     [TestCase("7%4", 3)]
     [TestCase("2^3", 8)]
     [TestCase("1e2", 100)]
+    [TestCase("2.0e2", 200)]
     [TestCase("0xFF", 255)]
     [TestCase("1010b", 10)]
+    [TestCase("0xFF*1010b", 2550)]
     public void Arithmetic_Works(string expr, decimal expected)
     {
         var result = _interp.Interpret(expr);
@@ -85,7 +87,7 @@ public class InputInterpreterTests
     [Test]
     public void ExpressionBinding_InvalidExpression_ProducesSoftError()
     {
-        _interp.Interpret("exp := bad + 1");
+        _interp.Interpret("exp :== bad + 1");
         var result = _interp.Interpret("exp");
         AssertSoftError(result, _interp);
     }