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×)÷
④
⑤12.5×2.5×12×
⑥[1.6-()×]÷.
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÷,
=;
④,
=,
=,
=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.
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.
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.
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÷,
=;
④,
=,
=,
=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.
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.
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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