I have one child in high school and its my own experience.

Take the actual San Pedro High Math Book for the first form,
any clever standard 5 student can solve all the exercises.

The 4 fist form high school classes are mixed with students have passes the PSE and students the failed the PSE.

The should be 4 classes
1 class for slow learners
2 classes for average learners
1 class for gifted students.

Today, the slow leaner have trouble to follow and the gifted students get bored. If a faster or brighter student is finish with his work, hi has to sit on his desk and wait till the LAST Student is finished. Its not allowed to do homework or anything else, just have to sit maybe for a half our and maybe you loose the interest for the school because its boring.

The standard in Italy, Germany, Belgium, Netherlands and Switzerland is far higher, as the standard in Belize.

The whole standard six is only repetition for the PSE.
In the European country's, the study is more linear and the repetition is only a minor part. In Belize you wasting a hell of time with repetition.