This reminds me of the time Feynman was teaching in Brazil and an abacus salesman cornered him. He could do the simple operations with simple numbers very quickly, but the harder the operation (multiplication, division, exponents, logs), the more Feynman pulled ahead. He tried to explain to the man how he did it, but the salesman couldn't follow. He just didn't understand numbers. This looks like it's doing the same thing -- setting students up neither to understand numbers in a way that aids learning more advanced operations nor to handle anything simple numbers. This is fine for the bottom 20% of the class but the rest of the class can, and needs to, take on a lot more so as not to do the sort of wheelspinning that forestalls preparedness for starting a STEM degree.
How does the Japanese multiplication work?
Okay, now do 75x99.
This reminds me of the time Feynman was teaching in Brazil and an abacus salesman cornered him. He could do the simple operations with simple numbers very quickly, but the harder the operation (multiplication, division, exponents, logs), the more Feynman pulled ahead. He tried to explain to the man how he did it, but the salesman couldn't follow. He just didn't understand numbers. This looks like it's doing the same thing -- setting students up neither to understand numbers in a way that aids learning more advanced operations nor to handle anything simple numbers. This is fine for the bottom 20% of the class but the rest of the class can, and needs to, take on a lot more so as not to do the sort of wheelspinning that forestalls preparedness for starting a STEM degree.