跟中文教材一样，第一课必定是命题。原命题，逆命题，否命题，逆否命题。原命题：如果You eat spinach,则You will get st...
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【Khan】逻辑推理 -
Pre-algebraKHan Academy APP里关于数学的课程还真是面儿广，从估计幼儿园水平的Early math，一直到大学一年级的Calculus. 从哪...
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可汗数学到底好在哪儿？我来体验一下
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