| 312-105= | 6.4÷0.8= | - = | × ÷ × = | 0.8×1.25= | 3÷ = |
2+ = | 2- + = | 3÷1%= | 3.25+7= | 1÷ = | -( )= |
解:
| 312-105=207, | 6.4÷0.8=8, | - = , | × ÷ × = , | 0.8×1.25=1, | 3÷ =9, |
2+ =3 , | 2- + =2 , | 3÷1%=300, | 3.25+7=10.25, | 1÷ = , | -( )= . |
分析:
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先把除法变成乘法,再根据乘法交换律和结合律简算;
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)根据减法的性质简算;其它题目根据运算法则直接求解.
点评:口算题目要求快速准确,能运用简算方法的要简算.
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