A new international comparison in math achievement has just been released. Here we have plotted the average achievement for children in the 8th grade against Income per person in each country. Here we have the same graph but with the results for 4th graders. As can be seen, the top five achievers are all East Asian countries.
You find the indicators under the heading “Education” -> “Achievement”. A higher score means better achievements in the test. The data is based on an international math test for children in 4th and 8th grade, from the TIMSS (Trends in International Mathematics and Science Study).