Grasple has multiple check methods using the Computer Algebra System (CAS) which can be used within the editor to indicate when the answer of a student should be marked correct/incorrect. A full list of current options can be found in this article.

This article covers the Ordered Collection check. There are three sections in this article:

- When to use the Ordered Collection check?
- Example cases
- How does the Ordered Collection check work?

## When to use the Ordered Collection check?

If you want to check whether the student answer is the same ordered collection as the correct ordered collection, you should use this check. A simple example would be: "*[4, 2x]*" is the same as "[2+2, x+x]" but not equal to "[2x, 4]".

A collection can contain

- numbers (e.g. 3 or pi)
- formulas (e.g. 3x+4)
- vectors/matrices

If the order of the collection is not important, use the Algebraically Equivalent check.

## Example cases

This method has the same logic as the Algebraically Equivalent check for unordered collections, but in addition checks whether the order of entries in the collection on the left-hand-side and right-hand-side are the same.

Collection can also contain vectors and matrices. The specific entries are checked using the Algebraically Equivalent check.

## How does the Ordered Collection check work?

Two collections are compared by for each entry subtracting the simplified left-hand-side and simplified right-hand-side and checking whether that equals to zero. Simplification is done using the mathematical rules within CAS.

For the ordered collection check the order of the entries in the left- and right-hand-side should be equal as well.

Do you want to know more about this check, whether you should use it for your exercise or any of the other checks? Please let us know via the chat icon in the right bottom of the screen!