diff --git a/kspread/valuecalc.cpp b/kspread/valuecalc.cpp
index 3a1182e54..2f6b4b8dd 100644
--- a/kspread/valuecalc.cpp
+++ b/kspread/valuecalc.cpp
@@ -433,9 +433,70 @@ bool ValueCalc::approxEqual (const Value &a, const Value &b)
   return (x < 0.0 ? -x : x)  <  ((aa < 0.0 ? -aa : aa) * DBL_EPSILON);
 }
 
-bool ValueCalc::strEqual (const Value &a, const Value &b)
+bool ValueCalc::strEqual (const Value &a, const Value &b, bool CS)
 {
-  return (converter->asString (a).asString() == converter->asString (b).asString());
+  TQString aa = converter->asString(a).asString();
+  TQString bb = converter->asString(b).asString();
+  if (!CS) {
+    aa = aa.lower();
+    bb = bb.lower();
+  }
+  return (aa == bb);
+}
+
+bool ValueCalc::strGreater (const Value &a, const Value &b, bool CS)
+{
+  TQString aa = converter->asString(a).asString();
+  TQString bb = converter->asString(b).asString();
+  if (!CS) {
+    aa = aa.lower();
+    bb = bb.lower();
+  }
+  return (aa > bb);
+}
+
+bool ValueCalc::strGequal (const Value &a, const Value &b, bool CS)
+{
+  TQString aa = converter->asString(a).asString();
+  TQString bb = converter->asString(b).asString();
+  if (!CS) {
+    aa = aa.lower();
+    bb = bb.lower();
+  }
+  return (aa >= bb);
+}
+
+bool ValueCalc::strLower (const Value &a, const Value &b, bool CS)
+{
+  return strGreater (b, a, CS);
+}
+
+bool ValueCalc::naturalEqual (const Value &a, const Value &b, bool CS)
+{
+  if (a.isNumber() && b.isNumber())
+    return approxEqual(a, b);
+  if (a.allowComparison(b))
+    return a.equal(b);
+  return strEqual(a, b, CS);
+}
+
+bool ValueCalc::naturalGreater (const Value &a, const Value &b, bool CS)
+{
+  if (a.isNumber() && b.isNumber())
+    return greater(a, b);
+  if (a.allowComparison(b))
+    return a.greater(b);
+  return strGreater(a, b, CS);
+}
+
+bool ValueCalc::naturalGequal (const Value &a, const Value &b, bool CS)
+{
+  return naturalGreater(a, b, CS) || naturalEqual(a, b, CS);
+}
+
+bool ValueCalc::naturalLower (const Value &a, const Value &b, bool CS)
+{
+  return naturalGreater(b, a, CS);
 }
 
 bool ValueCalc::greater (const Value &a, const Value &b)
diff --git a/kspread/valuecalc.h b/kspread/valuecalc.h
index 2d78211b2..5157fa4c6 100644
--- a/kspread/valuecalc.h
+++ b/kspread/valuecalc.h
@@ -106,7 +106,22 @@ class ValueCalc {
   /** numerical comparison */
   bool lower (const Value &a, const Value &b);
   /** string comparison */
-  bool strEqual (const Value &a, const Value &b);
+  bool strEqual (const Value &a, const Value &b, bool CS = true);
+  /** string comparison */
+  bool strGreater (const Value &a, const Value &b, bool CS = true);
+  /** string comparison - greater or equal */
+  bool strGequal (const Value &a, const Value &b, bool CS = true);
+  /** string comparison */
+  bool strLower (const Value &a, const Value &b, bool CS = true);
+  /** string or numerical comparison */
+  bool naturalEqual (const Value &a, const Value &b, bool CS = true);
+  /** string or numerical comparison */
+  bool naturalGreater (const Value &a, const Value &b, bool CS = true);
+  /** string or numerical comparison - greater or equal */
+  bool naturalGequal (const Value &a, const Value &b, bool CS = true);
+  /** string or numerical comparison */
+  bool naturalLower (const Value &a, const Value &b, bool CS = true);
+
   int sign (const Value &a);
 
   /** rounding */