The Nuffic Glossary is a list with explanations of terms used in Dutch education.
The rekentoets is a compulsory part of the school-leaving exam of all pupils in secondary education. It specifically tests the arithmetic skills. There are various levels of the test, corresponding with the various levels of secondary education.
Although all pupils have to take the test, the outcome of the test has no impact on the total exam result.
For more information check the website of the Dutch Ministry of Education (in Dutch).