diff --git a/src/main/java/org/math/R/AbstractR2jsSession.java b/src/main/java/org/math/R/AbstractR2jsSession.java
index 6c7743d..ce902dc 100644
--- a/src/main/java/org/math/R/AbstractR2jsSession.java
+++ b/src/main/java/org/math/R/AbstractR2jsSession.java
@@ -2307,7 +2307,7 @@ private static String replaceOperators(String expr) {
 
         // We consider differently the '-' operator in '2-3' to the '-' negative: '-3'.
         // So we replace -3 by î3 first, but 2-3 stays 2-3
-        expr = expr.replaceAll("([\\[\\{\\(\\-\\\\=*\\/^;%+:,><&|ôâêŝĝ\\n]) *-", "$1 î");
+        expr = expr.replaceAll("([\\[\\{\\(\\-\\\\=*\\/^;%+:,><&|ôâêŝĝ\\n]|return) *-", "$1 î");
 
         String stoppingCharacters = "-=*/^;%+:,><&|ôâêŝĝ\n"; // all operators but 'î'
         expr = expr.replaceAll("[)]/", ") /");
diff --git a/src/test/java/org/math/R/R2jsSessionTest.java b/src/test/java/org/math/R/R2jsSessionTest.java
index a96e8e9..df0bb86 100644
--- a/src/test/java/org/math/R/R2jsSessionTest.java
+++ b/src/test/java/org/math/R/R2jsSessionTest.java
@@ -1483,6 +1483,18 @@ public void testDecimalPoints() throws RException {
         assertEquals((Double) engine.eval("1e-31*1e-32"),  1e-63, 1e-75); //"normal" floating error of 1e-15 on multiplication
     }
 
+    @Test
+    public void testMinus() throws RException {
+        engine.eval("test <- function() { -100+100+5 }");
+        assert (Double) engine.eval("test()") == 5.0;
+        assert (Double) engine.eval("-3 -4") == -7;
+        assert (Double) engine.eval(" -3 -4") == -7;
+        assert (Double) engine.eval("( -3 -4)") == -7;
+        assert (Double) engine.eval(" ( -3 -4)") == -7;
+        assert (Double) engine.eval(" { -3 -4}") == -7;
+        assert ((double[]) engine.eval(" [ -3 -4]"))[0] == -7;
+    }
+
 //    @Test
 //    public void testEvaluationTime() throws RException, ScriptException, IOException {
 //        String MATH_JS_FILE = "/org/math/R/math.js";