1. **State the problem:** We need to find how many paper chains used more than $2 \frac{1}{2}$ containers of glitter. 2. **Understand the data:** The amounts of glitter used are given as fractional containers: 2, $2 \frac{1}{4}$, $2 \frac{1}{2}$, $2 \frac{3}{4}$, 3, $3 \frac{1}{4}$, $3 \frac{1}{2}$, $3 \frac{3}{4}$, 4, $4 \frac{1}{4}$. 3. **Identify data points above $2 \frac{1}{2}$:** From the graph, red 'X' marks are at $2 \frac{1}{2}$, $3 \frac{1}{2}$, $3 \frac{3}{4}$ (two marks), 4, and $4 \frac{1}{4}$. 4. **Count only those strictly greater than $2 \frac{1}{2}$:** These are $3 \frac{1}{2}$, $3 \frac{3}{4}$ (two marks), 4, and $4 \frac{1}{4}$. 5. **Calculate the total:** There are 1 mark at $3 \frac{1}{2}$, 2 marks at $3 \frac{3}{4}$, 1 mark at 4, and 1 mark at $4 \frac{1}{4}$. 6. **Sum the counts:** $1 + 2 + 1 + 1 = 5$ paper chains. **Final answer:** 5 paper chains used more than $2 \frac{1}{2}$ containers of glitter.