It is hard to be fair to a whole class; different children require different levels of attention. Some children are able to work independently, without any assistance.
They are able to get their head down and work through all the tasks that are set for them. These children like not to be distracted and often work better independently. Other children want and need the attention of an adult that is able to guide them. These children often need timely prompts to tell them to carry on their work. These children are better suited to work in a group where they are able to seek help from their classmates. Overall, it is hard to balance between the two and some might get upset that the others are getting more attention.
To get around this problem, you can sort the children into groups of ability and go around the tables to talk to them. This is a good way of making sure that all the children in the classroom get the same amount of attention. Additionally, you can ask questions to all the children. You can do this by writing all their names on a list and crossing them out as they answer a question.
This way ensures that all the children feel as If they are being given by attention by the teacher and this makes them feel happier and may lead them to putting their hand up more often. Moreover, it is a good way to also assess the children.