9.2×12 = | 37 ÷9= |
×21= | 5.089× = |
59× = | 12 ÷ = |
× ÷ × = | +( - )÷1 - = |
34×3.1+5.1×14-6 = | + + + + = |
3+ + + + + + = | 4.25×1.32×0.75÷(1 ×1 )= |
=115;(2)37
÷9,=
×
,=
;(3)
×21,=(1-
)×21,=1×21-
×21,=21-
,=20
;(4)5.089×
=0.05089;(5)59×
,=(58+1)×
,=58×
+1×
,=27+
,=27
;(6)12
÷
,=
×11,=137;
(7)
×
÷
×
,=(
×
)×(
×
),=1×
,=
;(8)
+(
-
)÷1
-
,=
+(
-
)×
-
,=
+
×
-
×
-
,=
+
-
-
,=(
+
)-(
+
),=1-1,
=0;
(9)34×3.1+5.1×14-6
,=105.4-71.4-6.8,
=34-6.8,
=40.8;
(10)
+
+
+
+
,=


+
-
+
-
,=
-
,=
;(11)3+
+
+
+
+
+
,=3×(1+
+
+
+
+
+
),=3×[1+(1-
)+(
)+(
-
)+(
-
)+(
-
)+(
-
)],=3×(+1-
+
+
-
+
-
+
-
+
-
),=3×(1+1
),=3×1
,=
;(12)4.25×1.32×0.75÷(1
×1
),=4.25×1.32×0.75÷1.32÷1.1875,
=(4.25×0.75÷1.1875)×(1.32×1.32),
=1.7×1,
=1.7.
分析:(1)先把分数化成小数,再计算;
(2)(6)根据除以一个数等于乘这个数的倒数计算;
(3)先把
化成1-
,再运用乘法分配律简算;(4)把5.089的小数点向左移动两位即可;
(5)把59分解成58+1,再运用乘法分配律简算;
(7)先把除法变成乘法,再运用乘法结合律简算;
(8)先把除法变成乘法,运用乘法分配律简算,再运用加法交换律和减法的性质简算;
(9)先算乘法,再算加减法;
(10)
=
,
=
…由此化简求解;(11)先提取因数3,然后再把剩下的分数分解;如
=
,
=
-
…;(12)先根据除法的性质,去掉小括号,再运用乘法结合律简算.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.