Topic textbook
The textbook lives as a dedicated section inside the topic with chapter overview and links back to practice.
Textbook chapters
If you need a concept refresher before training, open the relevant textbook chapter.
Proportion concept and properties
Check, build, and transform proportions; find unknown terms.
Direct and inverse proportionality. Scale
Apply direct/inverse proportionality and map scale in practical tasks.
Algebraic ratio properties
Evaluate expressions from known ratios and prove derived proportions.