"My grandpa and grandma live in Beijing."
Culturally speaking, 奶奶和爷爷 looks wrong to me because of the order. In English, we say "mom and dad," and "aunts and uncles," and "grandma and grandpa," but "Mr. and Mrs." Reversing the order of these phrases would sound weird in most cases. In Chinese, it's "爸爸妈妈," and "父母," and "爷爷奶奶."
Exactly and it is now August 2019 and nothing has changed. This is an abandoned course that gets no attention. The absurdity is that this lesson is all about removing the 的 for close family members, and they pull a dumb trick like this yet do nothing about it. Since when has a grandfather not been a close family member?
You would pay for this? I'm starting to think it is a course for masochists. You start out every day feeling good about learning Chinese but by the end you feel so frustrated by getting things wrong that are caused by their half-baked program. It is not like that with other courses here.