The content of "multiplication table" is the "enemy" I have known for many years. But for me, it still feels like an elf in the forest, ghostly and elusive. This time, I made up my mind to catch the tail of this "elf", let it shed its mysterious veil, and let me not be threatened and blocked by it again and again.

Corresponding strategies: (1) foreshadowing, highlighting the uniqueness of fractional multiplication commutative law and associative law;

(2) In the practice class, all kinds of variant questions are presented in turn, and at the same time, the problems are faced directly, and the error-prone questions are tried, thought and debated in class. The truth is indisputable.

With this layout, will this cunning "elf" always realize its true colors in my hands? Only practice will test!

After the third paragraph, you can write down your own mistakes in your study and the difference between non-negative multiplication, so don't do it for me. )