题目内容
脱式计算,能简算的要简算:
| 2 | 3 |
| 85×1 | 1÷[(4 |
解:(1)2
+4.6+4
+5.4,
=(2
+4
)+(4.6+5.4),
=7+10,
=17;
(2)3
×2
-2
×3
,
=2
×(3
-3
),
=
×
,
=1;
(3)85×1
+2.5÷4
,
=85×
+2.5×
,
=102+0.6,
=102.6;
(4)1÷[(4
-0.005×700)÷1
],
=1÷[(4
-3.5)÷1
],
=1÷[(4
-3
)÷1
],
=1÷[
÷1
],
=1÷[
×
],
=1÷
,
=2.
分析:(1)运用加法交换律与结合律简算;
(2)运用乘法分配律简算;
(3)先算除法和乘法,再算加法;
(4)先算小括号内的乘法,再算小括号内的减法,然后算中括号内的除法,最后算括号外的除法.
点评: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.
=(2
=7+10,
=17;
(2)3
=2
=
=1;
(3)85×1
=85×
=102+0.6,
=102.6;
(4)1÷[(4
=1÷[(4
=1÷[(4
=1÷[
=1÷[
=1÷
=2.
分析:(1)运用加法交换律与结合律简算;
(2)运用乘法分配律简算;
(3)先算除法和乘法,再算加法;
(4)先算小括号内的乘法,再算小括号内的减法,然后算中括号内的除法,最后算括号外的除法.
点评: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.
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