题目内容
用你喜欢的方法计算
①457÷25÷4
②35×27-7×35+35×2
③64+5.8+4.2+28
④333×99+333×97+333×98
⑤425÷25+575÷25
⑥52×19+81×52.
解:①457÷25÷4
=457÷(25×4),
=457÷100,
=4.57;
②35×27-7×35+35×2
=(27-7)×35+35×2,
=20×35+35×2,
=700+70,
=770;
③64+5.8+4.2+28
=64+(5.8+4.2)+28,
=64+10+28,
=102;
④333×99+333×97+333×98
=(99+97+98)×333,
=(100-1+100-3+100-2)×333,
=(300-6)×333,
=300×333-333×6,
=97902;
⑤425÷25+575÷25
=(425+575)÷25,
=1000÷25,
=40;
⑥52×19+81×52
=(19+81)×52,
=100×52,
=5200.
分析:①可根据一个数除以两个数,等于除以这两个数的积的除法性质计算.
②⑤⑥可根据乘法分配律计算;
③可根据加法结合律计算;
④可根据凑整法及乘法分配律计算;
点评:完成本题要注意分析式中数据的特点,然后快速准确得出答案.
=457÷(25×4),
=457÷100,
=4.57;
②35×27-7×35+35×2
=(27-7)×35+35×2,
=20×35+35×2,
=700+70,
=770;
③64+5.8+4.2+28
=64+(5.8+4.2)+28,
=64+10+28,
=102;
④333×99+333×97+333×98
=(99+97+98)×333,
=(100-1+100-3+100-2)×333,
=(300-6)×333,
=300×333-333×6,
=97902;
⑤425÷25+575÷25
=(425+575)÷25,
=1000÷25,
=40;
⑥52×19+81×52
=(19+81)×52,
=100×52,
=5200.
分析:①可根据一个数除以两个数,等于除以这两个数的积的除法性质计算.
②⑤⑥可根据乘法分配律计算;
③可根据加法结合律计算;
④可根据凑整法及乘法分配律计算;
点评:完成本题要注意分析式中数据的特点,然后快速准确得出答案.
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