计算下面各题,能简算的要简算.48×( 5 6 + 5 8 - 5 12 )1.25×3.2×0.257-7× 3 7 + 4 7 35×(1- 3 7 )÷ 5 12 8 17 ÷19+ 1 19 × 9 17 2 3 + 1 3 × 3 4 .
(1)48×(
5
6 +
5
8 -
5
12 ),
=48×
5
6 +48×
5
8 -48×
5
12 ,
=40+30-20,
=50;
(2)1.25×3.2×0.25,
=1.25×0.8×(4×0.25),
=1×1,
=1;
(3)7-7×
3
7 +
4
7 ,
=7-3+
4
7 ,
=4+
4
7 ,
=4
4
7 ;
(4)35×(1-
3
7 )÷
5
12 ,
=35×
4
7 ×
12
5 ,
=48;
(5)
8
17 ÷19+
1
19 ×
9
17 ,
=
8
17
1
19 +
1
19 ×
9
17 ,
=(
8
17 +
9
17 )×
1
19 ,
=
1
19 ;
(6)
2
3 +
1
3 ×
3
4 ,
=
2
3 +
1
4 ,
=
11
12 .