题目内容
计算下面各题,注意运用简便方法
| ①0.85×99 | ②8.52-(5.52+0.9) | ③3.12+3.12×99 |
| ④3.56-0.2+6.44-4.8 | ⑤1.45÷0.2+1.45×5. |
①0.85×99,
=0.85×(100-1),
=0.85×100-0.85×1,
=85-0.85,
=84.15;
②8.52-(5.52+0.9),
=8.52-5.52-0.9,
=3-0.9,
=2.1;
③3.12+3.12×99,
=3.12×1+3.12×99,
=3.12×(1+99),
=3.12×100,
=312;
④3.56-0.2+6.44-4.8,
=(3.56+6.44)-(0.2+4.8),
=10-5,
=5;
⑤1.45÷0.2+1.45×5,
=1.45×5+1.45×5,
=1.45×(5+5),
=14.5.
=0.85×(100-1),
=0.85×100-0.85×1,
=85-0.85,
=84.15;
②8.52-(5.52+0.9),
=8.52-5.52-0.9,
=3-0.9,
=2.1;
③3.12+3.12×99,
=3.12×1+3.12×99,
=3.12×(1+99),
=3.12×100,
=312;
④3.56-0.2+6.44-4.8,
=(3.56+6.44)-(0.2+4.8),
=10-5,
=5;
⑤1.45÷0.2+1.45×5,
=1.45×5+1.45×5,
=1.45×(5+5),
=14.5.
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