A common error encountered when children are asked to add two fractions is that they add the numerator with the numerator and the denominator with the denominator. What could be the most likely reason for such a misconception?

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?