Reference answer: 7,5
Key points: Mathematical method principle - enumeration method, number systems
74. To weigh items of integer masses from $1^{\sim} 100$ in one weighing using a balance scale, if the weights can only be placed on one side of the scale, then at least $\qquad$ weights are needed; if the weights can be placed on both sides of the scale, then at least $\qquad$ weights are needed.