Mainly the work is classified into 3 types they are
 the working less than required work 
the working more than required work
the working upto your work
children should work upto their limit they shouldnot work more than their limit .even it is better to work beyond their limit if they are worked more they will be stressed and they can"t work properly for next work and they cannot be effective
so we should support children to work upto their limit