问题 解答题
用简便方法计算.
1.7+3.98+
1
50
47
50
×51
5.73-3
8
17
+(4.27-2
9
17
45×2.08+1.5×37.6
99999×77778+33333×66666
362+548×361
362×548-186
1
1×4
+
1
4×7
+
1
7×10
+…+
1
97×100
1
2
+
1
4
+
1
8
+
1
16
+
1
32
答案

1.7+3.98+

1
50

=1.7+(3.98+0.02),

=1.7+4,

=5.7;

47
50
×51,

=

47
50
×(50+1),

=

47
50
×50+
47
50
×1,

=47+

47
50

=47

47
50

5.73-3

8
17
+(4.27-2
9
17
),

=5.73+4.27-(3

8
17
+2
9
17
),

=10-6,

=4;

45×2.08+1.5×37.6,

=1.5×62.4+1.5×37.6,

=1.5×(62.4+37.6),

=1.5×100,

=150;

99999×77778+33333×66666,

=99999×77778+33333×(3×22222),

=99999×77778+(33333×3)×22222,

=99999×77778+99999×22222,

=99999×(77778+22222),

=99999×100000,

=9999900000;

362+548×361
362×548-186

=(362+548×361)÷(362×548-186),

=[362+548×(362-1)]÷(362×548-186),

=[362-548+548×362]÷(362×548-186),

=(362×548-186)÷(362×548-186),

=1;

1
1×4
+
1
4×7
+
1
7×10
+…+
1
97×100

=

1
3
×[(1-
1
4
)+(
1
4
-
1
7
)+(
1
7
-
1
10
)+…+(
1
97
-
1
100
)],

=

1
3
×
99
100

=

33
100

1
2
+
1
4
+
1
8
+
1
16
+
1
32

=(1-

1
2
)+(
1
2
-
1
4
)+(
1
4
-
1
8
)+(
1
8
-
1
16
)+(
1
16
-
1
32
),

=1-

1
2
+
1
2
-
1
4
+
1
4
-
1
8
+
1
8
-
1
16
+
1
16
-
1
32

=1-

1
32

=

31
32

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