Adjectives masculine/feminine singular/plural

Activities were students generate hypotheses from observation, test the hypotheses and express a conclusion are HOT (High Order of Thinking). I’m using this flipchart to teach a “weird” grammatical concept of French. Adjectives agree in gender and number with the noun they describe.
The conclusion to this lesson is what would happen if this rule would exist in English. I lead the students to that type of sentence: The desk is green / the desks are greens.