题目内容
5.52-0.55-0.45 | 12.59+4.37-2.59 |
36.5-36.5×0.95 | 9.68-4.36+3.32-8.64 |
2.4×1.02 | 8.6÷0.25÷4 |
12.5×25×3.2 | 9.28×1.3+92.8×0.87. |
解:①5.52-0.55-0.45,
=5.52-(0.55+0.45),
=5.52-1,
=4.52;
②12.59+4.37-2.59,
=12.59-2.59+4.37,
=10+4.37,
=14.37;
③36.5-36.5×0.95,
=36.5×(1-0.95),
=36.5×0.05,
=1.825;
④9.68-4.36+3.32-8.64,
=9.68+3.32-(4.36+8.64),
=13-13,
=0;
⑤2.4×1.02,
=2.4×1+2.4×0.02,
=2.4+0.048,
=2.448;
⑥8.6÷0.25÷4,
=8.6÷(0.25×4),
=8.6÷1,
=8.6;
⑦12.5×25×3.2,
=(12.5×8)×(25×0.4),
=100×10,
=1000;
⑧9.28×1.3+92.8×0.87,
=92.8×(0.13+0.87),
=92.8×1,
=92.8.
分析:①5.52-0.55-0.45,根据减法的运算性质a-b-c=a-(b+c)简算;
②12.59+4.37-2.59,根据加、减法的运算性质a+b-c=a-c+b简算;
③36.5-36.5×0.95,运用乘法分配律简算;
④9.68-4.36+3.32-8.64,根据加、减法的运算性质简算;
⑤2.4×1.02,转化为:2.4×(1+0.02),运用乘法分配律简算;
⑥8.6÷0.25÷4,根据除法的运算性质a÷b÷c=a÷(b×c)简算;
⑦12.5×25×3.2,把3.2拆分为:8×0.4,运用乘法交换律和结合律简算;
⑧9.28×1.3+92.8×0.87,转化为:92.8×0.13+92.8×0.87运用乘法分配律简算.
点评:此题考查的目的是理解掌握加、减、除法的运算性质和乘法的运算定律,并且能够灵活运用这些运算性质和运算定律进行简便计算.
=5.52-(0.55+0.45),
=5.52-1,
=4.52;
②12.59+4.37-2.59,
=12.59-2.59+4.37,
=10+4.37,
=14.37;
③36.5-36.5×0.95,
=36.5×(1-0.95),
=36.5×0.05,
=1.825;
④9.68-4.36+3.32-8.64,
=9.68+3.32-(4.36+8.64),
=13-13,
=0;
⑤2.4×1.02,
=2.4×1+2.4×0.02,
=2.4+0.048,
=2.448;
⑥8.6÷0.25÷4,
=8.6÷(0.25×4),
=8.6÷1,
=8.6;
⑦12.5×25×3.2,
=(12.5×8)×(25×0.4),
=100×10,
=1000;
⑧9.28×1.3+92.8×0.87,
=92.8×(0.13+0.87),
=92.8×1,
=92.8.
分析:①5.52-0.55-0.45,根据减法的运算性质a-b-c=a-(b+c)简算;
②12.59+4.37-2.59,根据加、减法的运算性质a+b-c=a-c+b简算;
③36.5-36.5×0.95,运用乘法分配律简算;
④9.68-4.36+3.32-8.64,根据加、减法的运算性质简算;
⑤2.4×1.02,转化为:2.4×(1+0.02),运用乘法分配律简算;
⑥8.6÷0.25÷4,根据除法的运算性质a÷b÷c=a÷(b×c)简算;
⑦12.5×25×3.2,把3.2拆分为:8×0.4,运用乘法交换律和结合律简算;
⑧9.28×1.3+92.8×0.87,转化为:92.8×0.13+92.8×0.87运用乘法分配律简算.
点评:此题考查的目的是理解掌握加、减、除法的运算性质和乘法的运算定律,并且能够灵活运用这些运算性质和运算定律进行简便计算.
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