This article is much easier than that one.

This article is much easier than that one.
This article is much easier than that one.

This article is much easier than that one.
这篇文章比那篇容易多了

这篇文章比那篇简单多了.
easier than: 比...简单 加上much就是简单多了
that one: 那一个 这里指的是'那一个文章' 因为和它对比的是'this article'(这篇文章)

这篇文章比那篇文章容易得多。

这篇文章比那篇容易得多