Professor Chacha

Professor Chacha is a math teacher and educational psychologist. He has taught for more than 20 years in Mozambique, where most of his work is preparing students for the entrance exams that decide whether they get into college.

Those exams look a lot like American placement tests: multiple choice, timed, and heavy on algebra, percents, and word problems. Year after year, he sees students lose points to the same few traps, and his lessons are built around them.

He writes every practice question on this site from scratch, solves it step by step, and checks the arithmetic before it goes live. Questions from official tests are never copied here.