回复：我该怎么教三年级女儿数学呢?

Kids at that age turn to forget things. It is pretty normal. My son is pretty fast learner regarding math subject, but he still forgot thing after 2 or 3 months without practice. I am not teaching my son anymore, I found it was actully easy to let him teach himself. There are tons of youtub out there to teach kids long division, fraction and decimal. Some of them are very funny, kids love it. Just find some youtub for her, you will find she is learning without even notice it.