Reflections on the three levels of family education, school education and society education, make us deeply understand the advantages of this form of learning.

通过对传统家庭教育、学校教育、社会教育三个层面的反思，使我们深刻体会这种学习形式在当代的优势。

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Casio has redesigned the ClassPad series' software keyboard to make this new model easier to use, organizing functions to correspond to three levels of learning difficulty, beginning with basic functions used by everyone like fractions, square roots, and trigonometric functions, then advanced functions like differential calculus, complex compound numbers, and sigma calculations, and finally even more advanced calculations including piecewise and user-defined formulas.

ENGADGET: Casio's touchscreen graphing calculator arrives in 2013, makes the TI-84+ look dated