(1)
×(8 9
+1 4
)3 8
=
×8 9
+1 4
×8 9
3 8
=
+2 9
1 3
=
;5 9
(2)13×
+2÷3 4
+4 3
3 4
=13×
+2×3 4
+3 4
3 4
=(13+2+1)×
3 4
=16×
3 4
=12;
(3)12÷(
×4+4 5
×4)6 5
=12÷[(
+4 5
)×4]6 5
=12÷[2×4]
=12÷8
=1.5.