When we think of adjectives, we think of words like beautiful, nice, good, bad. There is a lot more to adjectives than this.
Adjectives are classified in various ways in different books and websites. Some say it has 3 types, some say 6, while some say 8. It doesn't matter what kind of divisions a child learns. What ultimately matters is whether a child is able to identify the adjectives in the given sentences or not.
Adjectives usually answer questions like which, whose, how many, what type, etc.
Why is it important, you may ask. And that's a valid question. It's easy to identify words like beautiful or good as adjectives in sentences. However, when the present participles or past participles or infinitives act like the adjectives of the sentence, then it's very easy to get confused between adjectives and verbs. If one has to convert the tenses of such sentences, mistakes are more likely to happen then.
For example, to convert "My time to play is over" into simple past tense if we take 'play' as a verb and convert it as " My time to played is over", it makes no sense.
Here in this sentence, which time is over? Time to play. Thus 'to play' is an infinitive that functions as an adjective of this sentence. The simple past tense of this sentence will be "My time to play was over."
Present participle as an adjective: I have running shoes.
Past participle as an adjective: I have a broken chair.
Infinitive phrase as an adjective: My need to please you is no more there.
Also, adjectives may be confused with nouns. We need to identify the adjectives so as not to err in subject-verb agreement.
My stationery item is/are missing.
In this sentence, 'stationery' modifies 'item' (which item?) and thus is an adjective. Hence the verb (is/are) cannot be chosen for stationery. The head of the noun phrase 'my stationery item' is 'item', which is singular. Hence, 'is missing'. If we convert this sentence into a plural, it becomes 'my stationery items are missing'. Since 'stationery' is an adjective, the rule of plurals doesn't affect it in this sentence.