[yanjuk]

I taught my two kids long division in about ten 40-minute sessions spread over 5 days. I sat with each child as we learnt the procedure. To begin with I held the pencil and asked questions, then the child took over the writing and I monitored to fix mistakes until finally the task could be performed/practiced solo.

In this one-on-one practice approach misconceptions are eliminated quickly at the start. It could not easily be replicated in a large group. Instead the approach in the article seems to be about groups of people identifying each other's misconceptions. Either way the effectiveness lies in avoiding bad habit formation.

If you look at YouTube each method of arithmetic has variants and you can pick the one that looks best. e.g. I chose a method of multiplication with consistent placing for the carries which reduced error considerably over what I was taught at school.