2.25: This rational number is obtained by taking the average of 2 and 3. It lies exactly in the middle between the two numbers.
2.5: This rational number is obtained by taking the average of 2.25 and 2.75. It lies closer to 3 than to 2.
2.75: This rational number is obtained by taking the average of 2.5 and 3. It lies closer to 3 than to 2.