An Antonym is a word opposite in meaning to another word, and this definition applies mainly adjectives although some other words such as: adverbs, verbs, and even abstract nouns also have antonyms.
Antonyms enrich our vocabulary providing multiple perspectives when communicating ideas.
Now, a synonym for the word Antonym is "contrasting" or "contrastive"
Thereby, the above statement can be completed like this:
"Contrasting/Contrastive words such as ‘similar/different and problem/solution' help students organize important information in textbooks."
