Subtracting the weight of the smaller brick from the larger gives us the weight difference:
4 3/8 lb - 2 1/3 lb. The two denominators are 8 and 3 respectively, resulting in an LCD of 24. Thus, our problem becomes:
4 9/24 - 2 8/24, which equals 2 1/24 lb. The weight difference is 2 1/24 lb.