diff --git a/src/Base/MatrixPyImp.cpp b/src/Base/MatrixPyImp.cpp
index 4391128f41..bb3501d3b2 100644
--- a/src/Base/MatrixPyImp.cpp
+++ b/src/Base/MatrixPyImp.cpp
@@ -182,11 +182,17 @@ PyObject * MatrixPy::number_power_handler (PyObject* self, PyObject* other, PyOb
         return new MatrixPy(Matrix4D());
 
     if(b < 0) {
-        b = 1+b;
-        a.inverse();
+        if (fabs(a.determinant()) > DBL_EPSILON)
+            a.inverseGauss();
+        else {
+            PyErr_SetString(Base::BaseExceptionFreeCADError, "Cannot invert singular matrix");
+            return 0;
+        }
+        b = -b;
     }
+
     auto res = a;
-    for(;b;--b)
+    for(--b;b;--b)
         res *= a;
     return new MatrixPy(res);
 }
diff --git a/src/Base/PlacementPyImp.cpp b/src/Base/PlacementPyImp.cpp
index cbdd2a134d..c1f6884925 100644
--- a/src/Base/PlacementPyImp.cpp
+++ b/src/Base/PlacementPyImp.cpp
@@ -363,11 +363,11 @@ PyObject * PlacementPy::number_power_handler (PyObject* self, PyObject* other, P
         return new PlacementPy(Placement());
 
     if(b < 0) {
-        b = 1+b;
+        b = -b;
         a.invert();
     }
     auto res = a;
-    for(;b;--b)
+    for(--b;b;--b)
         res *= a;
     return new PlacementPy(res);
 }
diff --git a/src/Base/RotationPyImp.cpp b/src/Base/RotationPyImp.cpp
index d3c17ed21c..9c16034275 100644
--- a/src/Base/RotationPyImp.cpp
+++ b/src/Base/RotationPyImp.cpp
@@ -440,11 +440,11 @@ PyObject * RotationPy::number_power_handler (PyObject* self, PyObject* other, Py
         return new RotationPy(Rotation());
 
     if(b < 0) {
-        b = 1+b;
+        b = -b;
         a.invert();
     }
     auto res = a;
-    for(;b;--b)
+    for(--b;b;--b)
         res *= a;
     return new RotationPy(res);
 }