( + )×48= | 12 ÷25= | ÷ = |
÷23+ × = | ÷ ÷ = | ×3÷ = |
( - × )÷ = | ( + )×32= | × + × = |
= | 88×( + )= | × ×16= |
+ × = | 44-72× = | = |
+
)×48,=
×48+
×48,=40+18,
=58;
(2)12
÷25,=
×
,=
;(3)
÷
,=
×(78-1),=
×78-
×1,=59-
,=58
;(4)
÷23+
×
,=
×
+
×
,=(
+
)×
,=1×
,=
;(5)
÷
÷
,=
÷(
×
),=
÷1,=
;(6)
×3÷
,=
×3×
,=
×
×3,=4×3,
=12;
(7)(
-
×
)÷
,=(
-
)×
,=
×
-
×
,=
-
,=
;(8)(
+
)×32,=
×32+
×32,=24+20,
=44;
(9)
×
+
×
,=
×(
+
),=
×1,=
;(10)
,=
×
,=
;(11)88×(
+
),=88×
+88×
,=33+2,
=35;
(12)
×
×16,=
×(
×16),=
×2,=
;(13)
+
×
,=
+
,=
;(14)44-72×
,=44-30,
=14;
(15)
,=
×(14+1),=
×15,=14.
分析:(1)(4)(7)(8)(9)(11)(15)运用乘法分配律简算;
(2)根据除以一个数等于除以这个数的倒数求解;
(3)先把除法变成乘法,再把77分解成(78-1),然后运用乘法分配律简算;
(5)根据连续除以两个数,等于除以这两个数的积简算;
(6)先把除法变成乘法,再运用乘法交换律简算;
(10)按照从左到右的顺序计算;
(12)运用乘法结合律简算;
(13)先算乘法再算加法;
(14)先算乘法,再算减法.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.