7.08÷(1.25×0.8)= | - + = | × ÷ × = | 5.38-(2.1+2.38)= |
( - )×63= | 0.5×(2.6-2.4)= | (0.18+0.9)÷0.9= | 3- - = |
=7.08÷1,
=7.08;
(2)
-
+
,=
+
-
,=1-
,=
;(3)
×
÷
×
,=
×
×
×
,=(
×
)×(
×
),=1×
,=
;(4)5.38-(2.1+2.38),
=5.38-2.38-2.1,
=3-2.1,
=0.9;
(5)(
-
)×63,=
×63-
×63,=9-7,
=2;
(6)0.5×(2.6-2.4),
=0.5×0.2,
=0.1;
(7)(0.18+0.9)÷0.9,
=1.08÷0.9,
=1.2;
(8)3-
-
,=3-(
+
),=3-1,
=2.
分析:(1)先算小括号里面的乘法,再算括号外的除法;
(2)运用加法结合律;
(3)先把除法变成乘法,再运用乘法结合律简算;
(4)(8)根据连续减去两个数,等于减去这两个数的和简算;
(5)运用乘法分配律简算;
(6)先算小括号里面的减法,再算括号外的除法;
(7)先算小括号里面的加法,再算括号外的除法.
点评:本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.