[Blindmath] how to use blackboard in classroom with sighted pupil

[IqbalHosen]

dear listers, could anyone please suggest me how to work on blackboard with the sighted students? we have some visually impaired teachers who have to work with sighted learners. they are facing problem for not being able to use blackboard in the classroom. i would be very happy if anyone kindly give any advice regarding this problem.
thanks and best regards to all.
iqbal.