For the mental maths part of your lesson instead of chanting numbers or the times table why not have a conga around the classroom?
For example, the class teacher calls: ‘5 times 5 is’ and the children call ’25’. It is a lot of fun, and I have found that children learn their times tables more easily.
This activity can be changed for addition and subtraction and adapted to suit your objective. Note that it is wise to set your ground rules first, and you will find children respond because they want to do it.