How is the gerund used in this sentence?-

His least favorite activity is playing scales

There is no gerund in that sentence. To be a gerund, the verb with the -ing ending needs to be used as a noun. In this sentence, "is playing" is the main verb of the sentence, in present progressive tense.

Verbs: http://members.cox.net/lenco1/grammarpractice/verbnav.htm

Gerunds: http://members.cox.net/lenco1/grammarpractice/verbalsnav.htm

In the sentence "His least favorite activity is playing scales," the gerund "playing" is used as the subject complement of the linking verb "is." The gerund phrase "playing scales" acts as a noun phrase and describes the activity that is the subject's least favorite.

In this sentence, the gerund "playing" is used as the subject complement. The subject of the sentence is "His least favorite activity," and the verb phrase "is playing" functions as a linking verb construction. The gerund "playing" is the noun version of the verb "play" and acts as the complement to the subject, describing the activity that is his least favorite.

To identify the gerund in a sentence, you can follow these steps:
1. Identify the verb in the sentence.
2. Determine if the verb is functioning as a noun by asking "What is the subject doing?"
3. If the verb is acting as a noun and ends in "-ing," it is likely a gerund.

In this case, the verb "playing" is acting as a noun because it is used to describe the activity. The "-ing" ending confirms that it is a gerund.