I would start by largely imitating the courses that already exist in the country of Singapore. They are pretty good examples of international best practice, and

I would start by largely imitating the courses that already exist in the country of Singapore. They are pretty good examples of international best practice, and they are available in English, the language of school instruction in Singapore. https://www.singaporemath.com/Singapore_Math_s/331.htm https://www.singaporemath.com/Singapore_Math_s/331.htm