Final answer:
The expression n + 2n/12 represents the number of items Brooklyn can put in each gift bag. The part of the expression that represents the total number of stickers she buys is 2n/12, which simplifies to n/6.
Step-by-step explanation:
The expression n + 2n/12 represents the number of items Brooklyn can put in each gift bag. In this expression, n represents the number of noisemakers she buys and 2n represents the number of stickers she buys because she buys twice as many stickers as noisemakers. The total number of stickers she buys is given by 2n/12, which simplifies to n/6.