We’ve got a pretty big new feature for Numbas this week – a whole new part type! The *matrix entry* part asks the student to enter a matrix.

In the past, we’ve hacked together questions where we ask the student to enter a matrix by putting a load of gapfills in a table. That was very laborious to set up, and the user experience for the student wasn’t particularly great.

The matrix entry part is meant to make all this a lot smoother – you give a JME matrix variable as the correct answer, and the student is shown a (optionally resizable) grid of cells to enter their answer.

It works like this:

The student picks the size of their answer, then enters numbers in each of the cells. It’s marked as correct if the matrix they give exactly matches the one you give.

If you want, you can lock the size of the answer matrix, so the student doesn’t have to be shown the size picker interface. That looks like this:

There are a few other options:

- You can award the marks proportionate to the number of correct cells, instead of a simple pass/fail.
- You can mark cells as correct if they’re within a given margin of error of the correct answer.
- The precision restriction options from the number entry part are also available here.
- You can allow the student to enter their answers as fractions (this is also available for number entry parts now)

You can see all that in action in this demo exam I created, containing a few simple-ish matrix entry questions. And of course, there’s documentation.