[Volume 1 of junior high school] how to simplify the formula with quotient! Definition and how to do it?

[Volume 1 of junior high school] how to simplify the formula with quotient! Definition and how to do it?

That is, the numerator divided by the denominator, or the denominator divided by the numerator, so that the two can no longer be divided
There is no common divisor between numerator and denominator

Are addition and subtraction of integers the same as merging
What's the relationship between the addition and subtraction of integers and merging of the same category? I've done a few things that are no different from merging the same category~~~

You're right
The addition and subtraction of integers is actually the merging of similar terms

The addition and subtraction of integers merge the similar terms is not to say why the coefficients are added and subtracted sometimes

The addition and subtraction of integers and the combination of similar terms are the addition and subtraction of coefficients
Why increase and decrease sometimes?
This is the sign of the term, which becomes the plus and minus sign in the formula
for example
2-3a+2a
=2+(-3+2)a
=2+(-1)a
=2-a