Websites like KiasuParents or various Reddit education communities often have threads where parents and tutors discuss specific "challenging" questions from the series.
In 4B, many mistakes happen because students forget to convert centimeters to meters or vice versa. my pals are here maths 4b workbook answers free top
If you are looking for "answers," you are likely working through these core chapters: my pals are here maths 4b workbook answers free top