48. An ancient British merchant had a 15-pound weight, which broke into 4 pieces after falling to the ground. Later, it was found that the weight of each piece was an integer number of pounds, and these 4 pieces could be used to weigh any integer weight from 1 to 15 pounds (the weights can only be placed on one side of the scale). Therefore, the weights of the 4 pieces of the weight are $\qquad$ pounds, $\qquad$ pounds, $\qquad$ pounds, $\qquad$ pounds.
Answer: $1,2,4,8$