Fixed, thanks. All math solutions will be equivalent. And it isn't a parlour trick. It's teaching kids to think about breaking down problems into smaller units

Fixed, thanks. All math solutions will be equivalent. And it isn't a parlour trick. It's teaching kids to think about breaking down problems into smaller units and composing a solution. The rote algorithms work, but training kids to execute an algorithm won't help them understand. The long form subtraction algorithm isn't a skill that carries over to multiplication. Breaking a problem into smaller components, composing a solution, and checking with your original estimate does carry over. And not just multiplication but programming as well.