diff --git a/mpmath/ctx_iv.py b/mpmath/ctx_iv.py
index 6c1f8857..4b0952b2 100644
--- a/mpmath/ctx_iv.py
+++ b/mpmath/ctx_iv.py
@@ -252,41 +252,28 @@ def _binary_op(f_real, f_complex):
             return g_complex(ctx, sval, tval)
     def lop_real(s, t):
         ctx = s.ctx
-        if not isinstance(t, ctx._types):
-            try:
-                t = ctx.convert(t)
-            except (ValueError, TypeError):
-                return NotImplemented
+        if not isinstance(t, ctx._types): t = ctx.convert(t)
         if hasattr(t, "_mpi_"): return g_real(ctx, s._mpi_, t._mpi_)
-        if hasattr(t, "_mpci_"):
-            return g_complex(ctx, (s._mpi_, mpi_zero), t._mpci_)
+        if hasattr(t, "_mpci_"): return g_complex(ctx, (s._mpi_, mpi_zero), t._mpci_)
         return NotImplemented
     def rop_real(s, t):
         ctx = s.ctx
-        if not isinstance(t, ctx._types):
-            try:
-                t = ctx.convert(t)
-            except (ValueError, TypeError):
-                return NotImplemented
+        if not isinstance(t, ctx._types): t = ctx.convert(t)
         if hasattr(t, "_mpi_"): return g_real(ctx, t._mpi_, s._mpi_)
-        if hasattr(t, "_mpci_"):
-            return g_complex(ctx, t._mpci_, (s._mpi_, mpi_zero))
+        if hasattr(t, "_mpci_"): return g_complex(ctx, t._mpci_, (s._mpi_, mpi_zero))
         return NotImplemented
     def lop_complex(s, t):
         ctx = s.ctx
-        if not isinstance(t, ctx._types):
+        if not isinstance(t, s.ctx._types):
             try:
-                t = ctx.convert(t)
+                t = s.ctx.convert(t)
             except (ValueError, TypeError):
                 return NotImplemented
         return g_complex(ctx, s._mpci_, t._mpci_)
     def rop_complex(s, t):
         ctx = s.ctx
-        if not isinstance(t, ctx._types):
-            try:
-                t = ctx.convert(t)
-            except (ValueError, TypeError):
-                return NotImplemented
+        if not isinstance(t, s.ctx._types):
+            t = s.ctx.convert(t)
         return g_complex(ctx, t._mpci_, s._mpci_)
     return lop_real, rop_real, lop_complex, rop_complex
 
diff --git a/mpmath/tests/test_matrices.py b/mpmath/tests/test_matrices.py
index 0b5bd8fe..25fdd697 100644
--- a/mpmath/tests/test_matrices.py
+++ b/mpmath/tests/test_matrices.py
@@ -178,9 +178,3 @@ def test_matrix_numpy():
     l = [[1, 2], [3, 4], [5, 6]]
     a = numpy.array(l)
     assert matrix(l) == matrix(a)
-
-def test_matrix_iv():
-    A = iv.matrix([[1, 2], [3, 4]])
-    two = iv.mpf(2)
-    assert A*two == two*A
-    assert two*A == iv.matrix([[iv.mpf(2), iv.mpf(4)], [iv.mpf(6), iv.mpf(8)]])