There are three main organisers of English language mathematics competitions for which questions sets are easily available on line, namely the UKMT (UK Mathematical Trust), the AMC (American Mathematics Competition) and UOW (The University of Waterloo, Canada).

Below are links to external websites that hold questions sets and answers for these competitions:

1. UKMT Junior Challenge (25 MCQs in 60 minutes);
2. AMC 8 (25 MCQs in 40 minutes);
3. UOW Gauss paper 2 (25 MCQs in 60 minutes).