| 8.54-1.47-2.53 | 12×( + - ) |
17.28-(7.28+ ) | ÷[( + )÷ ]. |
=8.54-(1.47+2.53),
=8.54-4,
=4.54;
(2)12×(
+
-
),=12×
+12×
-12×
,=3+4-2,
=5;
(3)17.28-(7.28+
),=17.28-7.28-0.75,
=10-0.75,
=9.25;
(4)
÷[(
+
)÷
],=
÷[
÷
],=
×
,=
.分析:(1)根据连减的简便方法计算即可;
(2)根据乘法分配律简便计算;
(3)去括号简算计算;
(4)先算小括号里的加法,再算中括号里的除法,再后算括号外面的除法.
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.