用简便方法计算(要写出主要简算过程).1.7+5150+3.98;17.625-(4.4+758)3.35×6.4×2+6.7×3.60.25×48×1.253.34-5÷17-317×4917-(117-127)×9.-数学

题文

用简便方法计算(要写出主要简算过程).
1.7+5
1
50
+3.98;
17.625-(4.4+7
5
8
)  
3.35×6.4×2+6.7×3.6
0.25×48×1.25 3.34-5÷17-
3
17
×4
9
17
-(
1
17
-
1
27
)×9.
题型:解答题  难度:中档

答案

(1)1.7+5
1
50
+3.98,
=1.7+(5
1
50
+3.98),
=1.7+9,
=10.7;

(2)17.625-(4.4+7
5
8
),
=17.625-4.4-7
5
8

=17.625-7
5
8
-4.4,
=10-4.4,
=5.6;

(3)3.35×6.4×2+6.7×3.6,
=(3.35×2)×6.4+6.7×3.6,
=6.7×6.4+6.7×3.6,
=6.7×(6.4+3.6),
=6.7×10,
=67;

(4)0.25×48×1.25,
=0.25×(6×8)×1.25,
=(0.25×6)×(8×1.25),
=1.5×10,
=15;

(5)3.34-5÷17-
3
17
×4,
=3.34-
5
17
-
12
17

=3.34-(
5
17
+
12
17
),
=3.34-1,
=2.34;

(6)
9
17
-(
1
17
-
1
27
)×9,
=
9
17
-(
1
17
×9-
1
27
×9),
=
9
17
-
9
17
+
1
3

=
1
3