> why I think long multiplication/division became popular? It's easier to grade homework. No, it became popular because it used to be necessary. Math educatio

> why I think long multiplication/division became popular? It's easier to grade homework. No, it became popular because it used to be necessary. Math education (at all levels) is designed to teach 'how' rather than 'what' and this made sense when computation was something you had to do on paper. As to why it hasn't adapted, my guess is politics. There are too many people who lack any capacity for abstract reasoning but squeak through math classes by memorizing rules and procedures. These people naturally make a fuss when the rules and procedures are taken away and they start doing poorly.