See the spreadsheets by Mike Hadden MatrixDeterimant and MatrixInverse, these enable you to check answers and see working out as well.
If you are looking for notes and examples on Matrices then the following are useful sources and appropriate for Advanced and degree level students.
Notes and examples
Chapter 9 on Matrices and Transformations from the CIMT Further Pure Mathematics A Level material,
Just the Maths,
The Math Centre
and The HELM Project. If you have not come across the HELM Project before, the project was designed to support the mathematical education of engineering students and includes an extensive collection of notes which include clear worked examples. You can see on the list that a very small number of titles are ‘not ready yet’; for the sake of completeness the complete set is hosted by the Open University. To access the Open University resources you will need to create an account (easy and free), this will also give you access to the numerous free online courses.