计算下列各题.①36×202-72②608×99+608③75×60%+24×+0.6④⑤14.85-1.58×8+31.2÷1.2.

发布时间:2020-08-04 15:13:50

计算下列各题.
①36×202-72
②608×99+608
③75×60%+24×+0.6

⑤14.85-1.58×8+31.2÷1.2.

网友回答

解:①36×202-72,
=36×202-36×2,
=(202-2)×36,
=200×36,
=7200;

②608×99+608,
=608×(99+1),
=608×100,
=60800;

③75×60%+24×+0.6,
=75×0.6+24×0.6+0.6,
=(75+24+1)×0.6,
=100×0.6,
=60;

④[4+(2.2-1)×]÷4.5,
=[4+(2-1)×]÷4,
=[4+×]÷4,
=[4+]×,
=×,
=1;

⑤14.85-1.58×8+31.2÷1.2,
=14.85-12.64+26,
=2.21+26,
=28.21.
解析分析:①把72看做36×2,运用乘法分配律简算;②根据数字特点,运用乘法分配律简算;③把百分数和分数化为小数,运用运用乘法分配律简算;④先算小括号内的,再算中括号内的,最后算括号外的;⑤先算乘除,再算加减.

点评:考查了运算定律与简便运算,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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