John-Li/my_programs — comment on commit 4a6ad5e981680d0821df872731f7e73d4eab6075
File: book/arrays/1_dimentional/task-7.rb line 3
By gmile:

They do differ. When you use `+=` you explicitly specify what should happen to `i`: it should be added to `sum`. But if you write `sum + i` then it's not really clear what happens, except of that you have added two numbers.