78
(3
+ 1
) · 15 = (
+
) · 15 =
· 15 =
· (5
- 1
) =
· (
-
) =
·
=
4
: ( 3
+ 2
) =
: (
+
) =
:
=
·
=
3
· 10 - 2
· 4 =
· 10 -
· 4 =
-
=
-
=