The South African Mathematics Olympiad (SAMO) is the official national mathematics competition of the country. It is a three round competition with interesting questions and nice prizes. The three rounds take place in March, May and September of each year.
Question papers and solutions of the last few years are available on this web site. The names of each year's individual prize winners and our committee members are also posted.
There are plenty of calculator apps in Google Play, but IDEAL WebMath is different because it shows students how to solve a problem. IDEAL WebMath can help students with addition, subtraction, multiplication, division, comparing fractions, ratios, proportions, place values, and rounding.
Nice stuff - ideal to add to a lesson introducing standard form (scientific notation) - wish they'd written the numbers the conventional way round though!