Question

which work done is negative or positive. a labour carrying bricks to the roof. or a child pulling a toy car along with them.

Answer 1

work done by the labour person carrying a brick to the roof is positive.  Because it increases the potential energy of the brick.

work done by the child pulling a toy car  is positive in case there is friction on the floor.
work done by the child pulling the toy car is 0, if the floor is horizontal and is very smooth.
work done by the child is positive, if he / she pulls the car toy up over a height.