diff --git a/py/modcmath.c b/py/modcmath.c
index 59fa76ee68..46a33d3a89 100644
--- a/py/modcmath.c
+++ b/py/modcmath.c
@@ -97,7 +97,7 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_log_obj, mp_cmath_log);
 STATIC mp_obj_t mp_cmath_log10(mp_obj_t z_obj) {
     mp_float_t real, imag;
     mp_obj_get_complex(z_obj, &real, &imag);
-    return mp_obj_new_complex(0.5 * MICROPY_FLOAT_C_FUN(log10)(real*real + imag*imag), MICROPY_FLOAT_C_FUN(atan2)(imag, real));
+    return mp_obj_new_complex(0.5 * MICROPY_FLOAT_C_FUN(log10)(real*real + imag*imag), 0.4342944819032518 * MICROPY_FLOAT_C_FUN(atan2)(imag, real));
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_cmath_log10_obj, mp_cmath_log10);
 
diff --git a/py/objcomplex.c b/py/objcomplex.c
index 027292a17a..6a403f6269 100644
--- a/py/objcomplex.c
+++ b/py/objcomplex.c
@@ -58,7 +58,10 @@ STATIC void complex_print(void (*print)(void *env, const char *fmt, ...), void *
         print(env, "%sj", buf);
     } else {
         mp_format_float(o->real, buf, sizeof(buf), 'g', 7, '\0');
-        print(env, "(%s+", buf);
+        print(env, "(%s", buf);
+        if (o->imag >= 0) {
+            print(env, "+");
+        }
         mp_format_float(o->imag, buf, sizeof(buf), 'g', 7, '\0');
         print(env, "%sj)", buf);
     }
@@ -69,7 +72,10 @@ STATIC void complex_print(void (*print)(void *env, const char *fmt, ...), void *
         print(env, "%sj", buf);
     } else {
         sprintf(buf, "%.16g", (double)o->real);
-        print(env, "(%s+", buf);
+        print(env, "(%s", buf);
+        if (o->imag >= 0) {
+            print(env, "+");
+        }
         sprintf(buf, "%.16g", (double)o->imag);
         print(env, "%sj)", buf);
     }