题目内容
(1)0.35-10-(0.2+6.37÷0.7)×0.5
(2)91×
+9÷13-1÷13×100
(3)(
-
)×17-
(4)53.5×1.9+61×1.25+41×8.1
(5)12×[(
+
)÷
]
( 6)
×
+56×
+
×
.
(2)91×
1 |
31 |
(3)(
4 |
51 |
4 |
71 |
3 |
71 |
(4)53.5×1.9+61×1.25+41×8.1
(5)12×[(
1 |
2 |
1 |
3 |
5 |
6 |
( 6)
7 |
9 |
14 |
15 |
1 |
9 |
1 |
9 |
7 |
15 |
分析:(1)先算0.35-10=-9.65,再算括号内的除法,然后算括号内的加法,再算括号外的乘法,最后算减法;
(2)先把原式变为91×
+9×
-
×100,然后运用乘法分配律简算;
(3)先运用乘法分配律计算(
-
)×17,然后运用减法的性质简算;
(4)把1.9看作2-0.1,,把61看作60+1,把41看作40+1,运用乘法分配律简算,在云用加法结合律简算;
(5)先算小括号内的,再算中括号内的,最后算括号外的;
(6)先把原式变为
×7×
+56×
+
×
,然后运用乘法分配律简算.
(2)先把原式变为91×
1 |
31 |
1 |
13 |
1 |
13 |
(3)先运用乘法分配律计算(
4 |
51 |
4 |
71 |
(4)把1.9看作2-0.1,,把61看作60+1,把41看作40+1,运用乘法分配律简算,在云用加法结合律简算;
(5)先算小括号内的,再算中括号内的,最后算括号外的;
(6)先把原式变为
1 |
9 |
14 |
15 |
1 |
9 |
1 |
9 |
7 |
15 |
解答:解:(1)0.35-10-(0.2+6.37÷0.7)×0.5,
=-9.65-(0.2+9.1)×0.5,
=-9.65-9.3×0.5,
=-9.65-4.65,
=-(9.65+4.65),
=-14.3;
(2)91×
+9÷13-1÷13×100,
=91×
+9×
-
×100,
=(91+9-100)×
,
=0×
,
=0;
(3)(
-
)×17-
,
=
×17-
×17-
,
=
-(
+
),
=
-1,
=
;
(4)53.5×1.9+61×1.25+41×8.1,
=53.5×(2-0.1)+(60+1)×1.25+(40+1)×8.1,
=53.5×2-53.5×0.1+60×1.25+1×1.25+40×8.1+1×8.1,
=107-5.35+75+1.25+324+8.1,
=(107+75+324)+(1.25-5.35+8.1),
=506+4,
=510;
(5)12×[(
+
)÷
],
=12×[
÷
],
=12×1,
=12;
( 6)
×
+56×
+
×
,
=
×7×
+56×
+
×
,
=(
+56+
)×
,
=63×
,
=7.
=-9.65-(0.2+9.1)×0.5,
=-9.65-9.3×0.5,
=-9.65-4.65,
=-(9.65+4.65),
=-14.3;
(2)91×
1 |
31 |
=91×
1 |
31 |
1 |
13 |
1 |
13 |
=(91+9-100)×
1 |
13 |
=0×
1 |
13 |
=0;
(3)(
4 |
51 |
4 |
71 |
3 |
71 |
=
4 |
51 |
4 |
71 |
3 |
71 |
=
4 |
3 |
68 |
71 |
3 |
71 |
=
4 |
3 |
=
1 |
3 |
(4)53.5×1.9+61×1.25+41×8.1,
=53.5×(2-0.1)+(60+1)×1.25+(40+1)×8.1,
=53.5×2-53.5×0.1+60×1.25+1×1.25+40×8.1+1×8.1,
=107-5.35+75+1.25+324+8.1,
=(107+75+324)+(1.25-5.35+8.1),
=506+4,
=510;
(5)12×[(
1 |
2 |
1 |
3 |
5 |
6 |
=12×[
5 |
6 |
5 |
6 |
=12×1,
=12;
( 6)
7 |
9 |
14 |
15 |
1 |
9 |
1 |
9 |
7 |
15 |
=
1 |
9 |
14 |
15 |
1 |
9 |
1 |
9 |
7 |
15 |
=(
98 |
15 |
7 |
15 |
1 |
9 |
=63×
1 |
9 |
=7.
点评:考查了分数、小数的四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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