Math homework

The same sister-in-law that I last posted about just wrote on Facebook that the same child was sent home with math homework today where the teacher had said, "I know you all don't know how to do half of the problems on this sheet, but just do what you can and I'll grade you on 'completion'". No way for them to learn the unknown skills; they're just supposed to fill in the worksheet so they can get credit. Why didn't the teacher just cut the worksheet in half then?

Luckily, my brother is very smart and used to work as an electrical engineer before going back to school to be a physician. He taught his son how to do the problems. But what about the rest of the students in my nephew's class? Who is filling in the gaps in their math knowledge?