diff --git a/js-assembler/runtime-src/js-numbers.js b/js-assembler/runtime-src/js-numbers.js
index 0192b47..f8294ce 100644
--- a/js-assembler/runtime-src/js-numbers.js
+++ b/js-assembler/runtime-src/js-numbers.js
@@ -240,7 +240,21 @@ if (typeof(exports) !== 'undefined') {
 
 
     // add: scheme-number scheme-number -> scheme-number
-    var add = makeNumericBinop(
+    var add = function(x, y) {
+        var sum;
+        if (typeof(x) === 'number' && typeof(y) === 'number') {
+            sum = x + y;
+            if (isOverflow(sum)) {
+		return (makeBignum(x)).add(makeBignum(y));
+            }
+        }
+        if (x instanceof FloatPoint && y instanceof FloatPoint) {
+            return x.add(y);
+        }
+        return addSlow(x, y);        
+    };
+
+    var addSlow = makeNumericBinop(
 	function(x, y) {
 	    var sum = x + y;
 	    if (isOverflow(sum)) {
@@ -284,7 +298,22 @@ if (typeof(exports) !== 'undefined') {
 
 
     // mulitply: scheme-number scheme-number -> scheme-number
-    var multiply = makeNumericBinop(
+    var multiply = function(x, y) {
+        var prod;
+        if (typeof(x) === 'number' && typeof(y) === 'number') {
+	    prod = x * y;
+	    if (isOverflow(prod)) {
+		return (makeBignum(x)).multiply(makeBignum(y));
+            } else {
+                return prod;
+            }
+        }
+        if (x instanceof FloatPoint && y instanceof FloatPoint) {
+            return x.multiply(y);
+        }
+        return multiplySlow(x, y);
+    };
+    var multiplySlow = makeNumericBinop(
 	function(x, y) {
 	    var prod = x * y;
 	    if (isOverflow(prod)) {
diff --git a/js-assembler/runtime-src/runtime.js b/js-assembler/runtime-src/runtime.js
index a3f5eee..5103845 100644
--- a/js-assembler/runtime-src/runtime.js
+++ b/js-assembler/runtime-src/runtime.js
@@ -840,7 +840,7 @@
             if (typeof(x) === 'number' && typeof(y) === 'number') {
                 sum = x + y;
                 if (sum < -9e15 || sum > 9e15) {
-                    return checkedAddSlowPath(M, Array.prototype.slice.call(arguments, 1));
+                    return plt.baselib.numbers.add(x, y);
                 }
                 return sum;
             } else {
@@ -881,7 +881,7 @@
             if (typeof(x) === 'number' && typeof(y) === 'number') {
                 prod = x * y;
                 if (prod < -9e15 || prod > 9e15) {
-                    return checkedMulSlowPath(M, Array.prototype.slice.call(arguments, 1));
+                    return plt.baselib.numbers.multiply(x, y);
                 }
                 return prod;
             } else {
diff --git a/version.rkt b/version.rkt
index 147b2e1..4aa1fca 100644
--- a/version.rkt
+++ b/version.rkt
@@ -7,4 +7,4 @@
 (provide version)
 (: version String)
 
-(define version "1.162")
+(define version "1.163")