From Activity 3, the text incorrectly uses 'It's many students in the area'. The correct usage for a number of people is 'There are', as explained in 'Use' section, point 3.
Class 6 › English Grammar and Composition › Chapter 7: Introductory 'There' & 'It' › Topic: Activity 1: Circling correct introductory words in an email
Aligned to the NCTB national curriculum.