What happens when students complete their grade-level assignment?

Some students work through Happy Numbers quickly enough to complete their assignment before the end of the school year. What happens when they reach this stage? By default, when your student starts the last module in an assignment list, the next one module (or the next grade module) is automatically added.

If you’d like to change the default setting and adjust the new assignment, you can always do it via your account on Happy Numbers.
How can I change the assignment?