diff --git a/lang/number.c b/lang/number.c
index b09c941..bd229e7 100644
--- a/lang/number.c
+++ b/lang/number.c
@@ -27,30 +27,30 @@
 	return num->value;
 }
 
-static void number_add(VmState state, Object obj, void *priv) {
-	(void)priv;
+#define OP_ADD (void *)1
+#define OP_MINUS (void *)2
+
+static void number_math(VmState state, Object obj, void *priv) {
 	int arg_count = vm_stack_depth(state);
-	abort_if(arg_count != 2, "number_add called without 2 arguments");
+	abort_if(arg_count != 2, "number_math called without 2 arguments");
 	Object arg1 = vm_stack_get(state, 1);
-	int added = number_value(obj) + number_value(arg1);
-	vm_stack_set(state, 0, number_create(added));
+	int result = 0;
+	if (priv == OP_ADD) {
+		result = number_value(obj) + number_value(arg1);
+	} else if (priv == OP_MINUS) {
+		result = number_value(obj) - number_value(arg1);
+	} else {
+		abort_msg("number_math called with invalid priv");
+	}
+	vm_stack_set(state, 0, number_create(result));
 	vm_stack_drop(state, 1);
 	object_drop(&arg1);
 }
 
-static void number_minus(VmState state, Object obj, void *priv) {
-	(void)priv;
-	int arg_count = vm_stack_depth(state);
-	abort_if(arg_count != 2, "number_minus called without 2 arguments");
-	Object arg1 = vm_stack_get(state, 1);
-	int subbed = number_value(obj) - number_value(arg1);
-	vm_stack_set(state, 0, number_create(subbed));
-	vm_stack_drop(state, 1);
-	object_drop(&arg1);
-}
-
-static struct object_call calls[] = {{.name = "Add", .handler = number_add},
-	{.name = "Minus", .handler = number_minus}, {.name = NULL, /* end */}};
+static struct object_call calls[] = {
+	{.name = "Add", .handler = number_math, .priv = OP_ADD},
+	{.name = "Minus", .handler = number_math, .priv = OP_MINUS},
+	{.name = NULL, /* end */}};
 
 static struct object_class num_class = {
 	.cleanup = number_cleanup,