This is answering very broadly from my general knowledge: In the USA, one tends to go to elementary school ages 4-10, then middle school 10-13, and high school from 13-18. This is the old English system that was in place until about 100 years ago, and still is in some parts of the UK. You don't take any exams, but rather you are given a grade point average (GPA, between 1 and 4) based on your work. Aged 18, you are given a GED (general education diploma?) which shows you've finished high school. If you want to go to university, you can take either the SAT or the ACT placement tests which give you a score by which universities judge you. University is much more expensive than in the UK, and lasts four years. In the UK, we go to primary school from 4-11, then secondary school from 11-16. When you are 16, you sit a series of exams called the GCSE (General Certificate of Secondary Education). When you finish those, you have a choice; you can either go onto Sixth Form, go to college or leave school altogether to work. If you go to college, you will study (usually) more vocational subjects for a qualification such as an NVQ or a BTEC, although it's possible to study A-levels there. If you want to go to university, you will study from 16-18 at a sixth form for your A-level qualification - most people take three or four of them. Universities then judge you on your grades in your GCSEs and A-levels, and you do a three-year course in England or a four-year one in Scotland. Tuition fees are around £9,000 per year.

Here in the United States of America, children attend school from ages 4-18. There are three levels of mandatory education. Elementary school is usually from grades Pre-Kindergarten to 5 or 6 and usually the age is to 12-13. Middle school is grades 6,7 and 8. The ages is usually 12-14. Then High School is grades 9-12 and kids usually graduate at 18 years old. After completion a High School Diploma is awarded and then students can choose to go to college or straight into the workforce. Exams are given throughout every stage of schooling and students that do not pass are usually held back and then made to repeat that grade again. A GED is a General Equivalency Diploma is earned by kids who dropped out of school early and later decide to take courses to make up for what they missed by dropping out and after passing the exam they are awarded a GED which is similar to a High School Diploma.

There would be many many differences, as many differences as there would be between Indonesia, malaysia, vietnam, philippines etc. There are many different terminology differences. There are big differences in scoring, assessment, milestones, technology, educational principles, funding. There are also big differences in how you get into third level education. Is there something in particular you wanted to know? I am no expert on either system, but the Irish system is a little like the English one.