I came across this method to perform subtraction using addition and not using the "borrow" concept, apparently because it is harder to learn it that way.
This method is referred to as "Austrian method" in wikipedia article
- Is it really hard for students to learn subtraction using "borrow method"
- Is the "austrian method", better than the borrow method?
- Are there any studies into which methods of teaching subtraction are more/less helpful to students?
I found reference to this method in the book "The Teaching of Arithmetic; a Manual for Teachers" by Paul Klapper, published in 1921
Has this "controversy" been settled by now?