题目内容
计算
(1)3
×1.25×2
×3.2
(2)35
×29+65
×29-
÷
(3)0.03÷[(14-2.25×
)÷60%]
(4)2
×0.65+2
×0.35-(2
+0.72)÷2
(5){[4-(2
-1
)×3.5]÷0.16-2
}×(2
-1
).
(1)3
| 8 |
| 11 |
| 1 |
| 2 |
(2)35
| 5 |
| 9 |
| 5 |
| 9 |
| 1 |
| 9 |
| 1 |
| 29 |
(3)0.03÷[(14-2.25×
| 8 |
| 15 |
(4)2
| 5 |
| 6 |
| 5 |
| 6 |
| 2 |
| 5 |
| 22 |
| 25 |
(5){[4-(2
| 1 |
| 7 |
| 1 |
| 5 |
| 3 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
分析:(1)先把3.2分解成8×0.4,再运用乘法结合律简算;
(2)先把除法变成乘法,然后两次运用乘法分配律简算;
(3)先算小括号里面的乘法,再算小括号里面的减法,然后算中括号里面的除法,最后算括号外的除法;
(4)先算小括号里面的加法,再运用乘法分配律简算;
(5)先运用乘法分配律计算中括号里面的运算,再算大括号里面的除法,然后算大括号里面的减法,最后再运用乘法分配律简算.
(2)先把除法变成乘法,然后两次运用乘法分配律简算;
(3)先算小括号里面的乘法,再算小括号里面的减法,然后算中括号里面的除法,最后算括号外的除法;
(4)先算小括号里面的加法,再运用乘法分配律简算;
(5)先运用乘法分配律计算中括号里面的运算,再算大括号里面的除法,然后算大括号里面的减法,最后再运用乘法分配律简算.
解答:解:(1)3
×1.25×2
×3.2,
=3
×(1.25×2.5×0.4×8),
=3
×[(1.25×8)×(2.5×0.4)],
=3
×(10×1),
=3
×10,
=
;
(2)35
×29+65
×29-
÷
,
=35
×29+65
×29-
×29,
=(35
+65
-
)×29,
=101×29,
=(100+1)×29,
=100×29+1×29,
=2900+29,
=2929;
(3)0.03÷[(14-2.25×
)÷60%],
=0.03÷[(14-1.2)÷0.6],
=0.03÷[12.8÷0.6],
=0.03÷
,
=
;
(4)2
×0.65+2
×0.35-(2
+0.72)÷2
,
=2
×0.65+2
×0.35-3.12÷2
,
=2
×(0.65+0.35)-3.12÷2
,
=2
×1-3.12÷2
,
=2
-1
,
=1
;
(5){[4-(2
-1
)×3.5]÷0.16-2
}×(2
-1
),
={[4-(
×3.5-
×3.5)]÷0.16-2
}×(2
-1
),
={[4-(7.5-4.2)]÷0.16-2
}×(2
-1
),
={[4-3.3]÷0.16-2
}×(2
-1
),
={0.7÷0.16-2
}×(2
-1
),
={
-
}×(2
-1
),
=
×(2
-1
),
=
×
-
×
,
=
-
,
=
.
| 8 |
| 11 |
| 1 |
| 2 |
=3
| 8 |
| 11 |
=3
| 8 |
| 11 |
=3
| 8 |
| 11 |
=3
| 8 |
| 11 |
=
| 410 |
| 11 |
(2)35
| 5 |
| 9 |
| 5 |
| 9 |
| 1 |
| 9 |
| 1 |
| 29 |
=35
| 5 |
| 9 |
| 5 |
| 9 |
| 1 |
| 9 |
=(35
| 5 |
| 9 |
| 5 |
| 9 |
| 1 |
| 9 |
=101×29,
=(100+1)×29,
=100×29+1×29,
=2900+29,
=2929;
(3)0.03÷[(14-2.25×
| 8 |
| 15 |
=0.03÷[(14-1.2)÷0.6],
=0.03÷[12.8÷0.6],
=0.03÷
| 64 |
| 3 |
=
| 9 |
| 6400 |
(4)2
| 5 |
| 6 |
| 5 |
| 6 |
| 2 |
| 5 |
| 22 |
| 25 |
=2
| 5 |
| 6 |
| 5 |
| 6 |
| 22 |
| 25 |
=2
| 5 |
| 6 |
| 22 |
| 25 |
=2
| 5 |
| 6 |
| 22 |
| 25 |
=2
| 5 |
| 6 |
| 1 |
| 12 |
=1
| 3 |
| 4 |
(5){[4-(2
| 1 |
| 7 |
| 1 |
| 5 |
| 3 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
={[4-(
| 15 |
| 7 |
| 6 |
| 5 |
| 3 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
={[4-(7.5-4.2)]÷0.16-2
| 3 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
={[4-3.3]÷0.16-2
| 3 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
={0.7÷0.16-2
| 3 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
={
| 70 |
| 16 |
| 35 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
=
| 35 |
| 16 |
| 22 |
| 84 |
| 49 |
| 60 |
=
| 35 |
| 16 |
| 95 |
| 42 |
| 35 |
| 16 |
| 109 |
| 60 |
=
| 475 |
| 96 |
| 545 |
| 192 |
=
| 192 |
| 405 |
点评:本题计算较复杂,要注意分析式中数据,运用合适的简便方法计算.
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