diff --git a/lib/less/parser.js b/lib/less/parser.js
index 0658a3b9..67a71f75 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -782,7 +782,8 @@ less.parser = {
         addition: function () {
             var m, a, op;
             if (m = $(this.multiplication)) {
-                if ((op = $(/[-+]\s+/g)) && (a = $(this.addition))) {
+                if ((op = $(/[-+]\s+/g) || (input[i - 1] != ' ' && $(/[-+]/g))) &&
+                    (a = $(this.addition))) {
                     return new(tree.Operation)(op, [m, a]);
                 } else {
                     return m;