After teaching the topic 'Congruence of 2D figures', a middle school teacher starts a discussion with the students to assess their understanding. During the discussion, one student said, 'Two regions having the same area are also congruent.' Which of the following statements is correct with respect to the student's response?

A mathematics teacher of Class II gives the following word problem on addition to the students: 'A bag contains 4 mangoes and 6 more mangoes are put into it. How many mangoes are there in the bag in total?' This type of word problem belongs to which of the following structures of addition?

A teacher wrote the number 308 on the blackboard and asked the children to read it aloud. A child said, 'It is thirty-eight.' Which of the following is the most appropriate strategy to rectify the error made by the child?