| ×3 | |
![]() | ×17+ ×17 | ![]() |
20×( ) | 24×( ) | |
( ) |
×
×
=
;(2)
+
×3,=
+
,=
;(3)
×
+
×
,=
×(
+
),=
×1,=
;(4)
×
-
,=
-
,=
;(5)
×17-
×17,=(
-
)×17,=1×17,
=17;
(6)
-
-
-
,=
-(
+
+
),=
-1,=-
;(7)20×(
-
+
),=20×
-20×
+20×
,=5-4+10,
=11;
(8)24×(
-
+
),=24×
-24×
+24×
,=20-18+16,
=18;
(9)
×
+
×
=
×(
+
),=
×
,=
;(10)
-(
-
)=
-
+
,=
.分析:(1)约分计算;
(2)先算乘法,再算加法;
(3)(5)(7)(8)(9)运用乘法分配律简算;
(4)先算乘法,再算减法;
(6)(10)运用减法的性质简算.
点评:此题考查了四则混合运算,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.
×3


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)
(
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