+ = | - = | = | = | = | = |
= | = | 6:15= | 0.25:0.4= | : = | 0.6: = |
解: + = , | - = , | =64, | =81, | = , | = , |
= , | = , | 6:15=0.4, | 0.25:0.4=0.625, | : = , | 0.6: = . |
分析:异分母分数相加减,先通分,化成同分母的分数再计算;
分数乘法:分子相乘的积做分子,分母相乘的积做分母;
分数除法:除以一个数等于乘这个数的倒数;
求比值:用比的前项除以比的后项即可.
点评:本题考查了简单的分数运算,计算时要细心,注意把结果化成最简分数.
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