Then and Than, I find, are words that are not really TAUGHT to anyone, yet everyone expects you to know them. I’ve seen native English speakers confuse the two as well as ESL students. Hopefully this post will help you remember the difference between the two.
Then works mostly with time. It means “at that time” or “immediately following” something else. For example, “I went to the store, then to the movies.” I went to the store first, and went to the movies “immediately following” the store. “I’ll show you the phone then,” which would mean “at that time.” There are other examples of using then, such as “If…then” statements. For example, “If it is raining outside, then I will bring my umbrella.”
Less common examples of then include “in addition” and “in that case.” An example of the first would be, “He wanted the down payment and then interest too.” An example of the second would be, “If you want it, take it then.”
Than is used for comparisons. In math, when you see > or <, they’re called the “greater than” or “less than” signs. Why? Because they’re not discussing time–so they will not be “greater then” or “less then.” They’re establishing a comparison that one number is bigger than another.
Ok, now for the nitty gritty grammar stuff that you guys might not understand, but I’ll try to simplify it for you. Since than is used with comparisions, it’s also most commonly used with a comparative adjective or adverb. So think of words that establish a comparison–better, worse, etc. Something can’t just be “better,” it needs to be “better than” something else. So let’s look at an example: “She’s better at math than I am.” The comparison is like math– She > me. Another one: “It is far greater to be of sound mind than sound spirit.” Notice the word GREATER establishes the comparison.
I’ll give you a little memory hook to remember these words: There’s an “e” in time and an “e” in then—then most often deals with time. There’s an “a” in compare and an “a” in than–than deals with comparisons. Hope this helped, and good luck!