(1)54×
+45÷20+1 20
,1 20
=(54+45+1)×
,1 20
=100×
,1 20
=5;
(2)(
+1 6
+1 8
)×24,1 24
=
×24+1 6
×24+1 8
×24,1 24
=4+3+1,
=8;
(3)
?(3 7
?3 4
),4 7
=
+3 7
?4 7
,3 4
=1?
,3 4
=
;1 4
(4)3×
十4÷3 7
.7 3
=(3+4)×
,3 7
=7×
,3 7
=3.