It seems that whenever we look for resources on pattern activities we see reminders to pay attention to the pattern unit. What is that all about? Why does it matter? Shouldn’t it be enough to know that ABABAB is followed by A? Why make it more complicated?

To figure this out, let’s start with a few questions:

1. What comes next in the following pattern? ABCAB?
2. What comes next in the following pattern? ABCABDABCABD?

What did you answer for the first question? What did you answer for the second question? How did you decide what came next for each of these questions? Look at the italicized letters. If you answered C for the first question, how did you know that it was not D or some other letter?

You could ask the same questions with block patterns.

By now, you may have discovered that you are lacking some information in the first question for both the letter and block patterns. Specifically, there isn’t a pattern! Let’s rewrite the first questions, providing the information that we need to figure out what the pattern is:

What comes next in the following pattern? ABCABC ?

What comes next in the following pattern?

Now there is a pattern, and that pattern is a repeating pattern with a pattern unit (the pattern core that is repeated) of ABC or blue–red–yellow. In order for something to have a pattern, we need to see the entire pattern repeated. Otherwise, it could just be the beginning of an unfinished pattern. The part (or section) that is repeated is the pattern unit. And, that is why a pattern unit is important!