1, the remainder was originally defined in the division of integers, so the concept of remainder cannot be used in the operation of fractions.

I remember hearing a story before: the teacher taught the landlord's children to write. "One" is a horizontal line, "two" is two horizontal lines and "three" is three horizontal lines. After hearing this, the landlord's children ran away happily, saying that they could write all the figures. If the teacher does not explain "intuitive understanding of the reality of plus sign and equation", students may not be able to get 2+3 = 2 by analogy with 1+ 1=2. 4+5=?