As far as I can tell, from looking at my friends' kids' homework, it attempts to teach math about three different ways. This is because different people learn in different ways, so it makes sense, but it's confusing to parents who received the One Right Way sort of education.
Who get to learn it and be tested over it a number of different ways.
If they got it, they should skip ahead. If they didn't, they should go to the next method without penalty. Sort of a really, really heinous problem in differentiation by parts.