
(2)

(3)[(35.16×0.25+38.42÷2)×0.2-1.63-2.36]÷0.25
(4)
.解:(1)975×0.25+9
×76-9.75,=9.75×25+9.75×76-9.75,
=(25+76-1)×9.75,
=100×9.75,
=975;
(2)8
÷[7.8+
×(2
-1.15)],=8
÷[7.8+
×(
-
)],=8
÷[7.8+
×
],=8
÷[7.8+1],=
÷8.8,=

,=1;
(3)[(35.16×0.25+38.42÷2)×0.2-1.63-2.36]÷0.25,
=[(8.79+19.21)×0.2-(1.63+2.36)]÷0.25,
=[28×0.2-3.99]÷0.25,
=[5.6-3.99]÷0.25,
=1.61÷0.25,
=6.44;
(4)1+2
+3
+4
+5
+6
+7
+8
,=(1+2+3+4+5+6+7+8)+(
+
+
+
+
+
+
),=(1+8)×8÷2+(
-
+
-
+
-
+
-
+
-
+
-
+
-
),=36+(
-
),=36+
,=36
.分析:(1)根据积不变的规律,把975×0.25变成9.75×25,然后运用乘法分配律的逆运算简算;
(2)按运算顺序进行计算,先算小括号内的,再算中括号内的,最后算括号外的;
(3)按运算顺序进行计算,先算小括号内的,再算中括号内的,最后算括号外的;
(4)把每个分数拆成整数和分数两部分,整数与整数相加,分数与分数相加;整数相加,用高斯求和公式计算,分数又可拆成两个分数相减的形式,然后通过加、减相互抵消,求出结果.
点评:此题考查了学生对四则混合运算顺序的掌握情况,以及运用运算定律与运算技巧,巧妙解答的能力.