题目内容
计算(能简算的要写出简算过程)
①7968-2968÷28×27
②5.47-3
+3.63-2
③(8.8-23.4×
)÷
④0.3×1
+6
×
⑤12.5×2.5×12×
⑥[1.6-(
-
)×
]÷
.
①7968-2968÷28×27
②5.47-3
5 |
9 |
4 |
9 |
③(8.8-23.4×
1 |
3 |
5 |
9 |
④0.3×1
4 |
9 |
5 |
9 |
3 |
10 |
⑤12.5×2.5×12×
8 |
3 |
⑥[1.6-(
6 |
5 |
4 |
15 |
3 |
7 |
2 |
3 |
分析:①先算除法,再算乘法,最后算减法;
②根据加法交换律和结合律进行计算;
③先算乘法,再算减法,最后算除法;
④根据乘法分配律进行计算;
⑤根据乘法交换律和结合律进行计算;
⑥先算小括号里面的减法,再算中括号里面的乘法,再算中括号里面的减法,最后算除法.
②根据加法交换律和结合律进行计算;
③先算乘法,再算减法,最后算除法;
④根据乘法分配律进行计算;
⑤根据乘法交换律和结合律进行计算;
⑥先算小括号里面的减法,再算中括号里面的乘法,再算中括号里面的减法,最后算除法.
解答:解:
①7968-2968÷28×27,
=7968-106×27,
=7968-2862,
=5106;
②5.47-3
+3.63-2
,
=(5.47+3.63)-(3
+2
),
=9-6,
=3;
③(8.8-23.4×
)÷
,
=(8.8-7.8)÷
,
=1÷
,
=
;
④0.3×1
+6
×
,
=0.3×1
+6
×0.3,
=0.3×(1
+6
),
=0.3×8,
=2.4;
⑤12.5×2.5×12×
,
=12.5×2.5×(4×8),
=(12.5×8)×(2.5×4),
=100×10,
=1000;
⑥[1.6-(
-
)×
]÷
,
=[1.6-
×
]÷
,
=[1.6-0.4]÷
,
=1.2÷
,
=1.8.
①7968-2968÷28×27,
=7968-106×27,
=7968-2862,
=5106;
②5.47-3
5 |
9 |
4 |
9 |
=(5.47+3.63)-(3
5 |
9 |
4 |
9 |
=9-6,
=3;
③(8.8-23.4×
1 |
3 |
5 |
9 |
=(8.8-7.8)÷
5 |
9 |
=1÷
5 |
9 |
=
9 |
5 |
④0.3×1
4 |
9 |
5 |
9 |
3 |
10 |
=0.3×1
4 |
9 |
5 |
9 |
=0.3×(1
4 |
9 |
5 |
9 |
=0.3×8,
=2.4;
⑤12.5×2.5×12×
8 |
3 |
=12.5×2.5×(4×8),
=(12.5×8)×(2.5×4),
=100×10,
=1000;
⑥[1.6-(
6 |
5 |
4 |
15 |
3 |
7 |
2 |
3 |
=[1.6-
14 |
15 |
3 |
7 |
2 |
3 |
=[1.6-0.4]÷
2 |
3 |
=1.2÷
2 |
3 |
=1.8.
点评:四则运算,先弄清运算顺序,然后再进行计算,能简算的要简算.
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