【Question 3】There are weights of 1 gram, 2 grams, 3 grams, and 5 grams, each one piece. These can be used to weigh from 1 to 11 grams. Some weights can be measured in more than one way, for example, 3 grams can be measured using the 3-gram weight, or using the 1-gram and 2-gram weights. Therefore, the weight that requires at least 3 weights to be measured is $\qquad$ grams.
1 gram, 2 grams, 3 grams, 5 grams at least require 1 weight;
4 grams, 6 grams, 7 grams, 8 grams at least require 2 weights;
9 grams, 10 grams, 11 grams at least require 3 weights.