I’ve had 4 years of undergraduate math courses, two years of graduate math courses, and I have taught graduate level math courses. I had never seen the “lattice” method, the Egyptian method, or any of these other alternative algorithms until last year when I looked at Everyday Math homework. Students don’t need them, and those methods will not help a student move onto higher mathematics.
I would have been laughed out of my college classes if I used the “partial sums” method to add. I wouldn’t have been able to take differential equations if I hadn’t mastered long division. There is a reason why traditional algorithms (the math methods you learned in school to add, subtract, multiply and divide) are needed. Traditional algorithms are needed to understand higher mathematics in college. It is extremely important that they are practiced until they are mastered. In fact, the new Common Core State math standards recommend teaching the standard algorithms.
You might think there is no reason not to offer alternative algorithms, as long as they also teach the traditional methods, but I have three reasons why the teaching of alternative programs is a problem.