Answer 1

1. In-place operator stores the calculation result and store back into the variable,

2. Example
a = 2
a+=3 #equivalent to a = a + 3
#a becomes 5

+= is in-place operator

3. Sololearn Python has this:
https://www.sololearn.com/learn/Python/2429/

4. There are also
-=
*=
/=
%=

5. Try them in code playground. Show your practice here