To find the midpoint between two coordinates you have to find the average between the Xs and Yx of each pair of coordinates. Two find an average you add the numbers together and divide by how many there are. So we will add the two Xs together nd divide by two which gives us the x coordinate of the midpoint. The same can be done for Y.
X midpoint = (2+6)/2 = 8/2 = 4
Y midpoint = (6+3)/2 = 9/2
So the coordinate pair for the midpoint is (4, 9/2)