题目内容
计算下列各题,能简算的要简算.
(1).1.5×8.4+3×
+15×l0%;
(2)
+
;
(3)
;
(4)
;
(5)1110÷
;
(6)5-
.
解:
(1)1.5×8.4+3×
+15×l0%,
=1.5×8.4+1.5×0.l+3×
,
=1.5×(8.4+0.1)+0.9,
=1.5×8.5+0.9,
=12.75+0.9,
=13.65;
(2)
+
,
=
+(1-
),
=
+
,
=
;
(3)
,
=
,
=
,
=1+
,
=1
;
(4)
,
=
,
=
,
=
,
=
;
(5)1110÷
,
=1110÷
,
=1110÷[65-55],
=1110÷10,
=111;
(6)5-
,
=5-
,
=5-[3-2.5]÷0.125,
=5-0.5÷0.125,
=5-4,
=1.
分析:(1)根据乘法分配律进行计算;
(2)先算乘法,再算减法,最后算加法;
(3)根据乘法分配律进行计算;
(4)根据连减的性质计算括号里面的,最后算除法;
(5)根据乘法分配律进行计算;
(6)根据连减的性质计算括号里面的,再算除法,最后算减法.
点评:考查了运算定律与简便运算,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律简便计算.
(1)1.5×8.4+3×
=1.5×8.4+1.5×0.l+3×
=1.5×(8.4+0.1)+0.9,
=1.5×8.5+0.9,
=12.75+0.9,
=13.65;
(2)
=
=
=
(3)
=
=
=1+
=1
(4)
=
=
=
=
(5)1110÷
=1110÷
=1110÷[65-55],
=1110÷10,
=111;
(6)5-
=5-
=5-[3-2.5]÷0.125,
=5-0.5÷0.125,
=5-4,
=1.
分析:(1)根据乘法分配律进行计算;
(2)先算乘法,再算减法,最后算加法;
(3)根据乘法分配律进行计算;
(4)根据连减的性质计算括号里面的,最后算除法;
(5)根据乘法分配律进行计算;
(6)根据连减的性质计算括号里面的,再算除法,最后算减法.
点评:考查了运算定律与简便运算,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律简便计算.
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