If you would like to know how much did the seedling grow during the 2nd year, you can calculate this using the following steps:
during the first year: 2 1/4 feet + 1 1/6 feet = 9/4 + 7/6 = 27/12 + 14/12 = 41/12 = 3 5/12 feet
after two years: 5 feet - 3 5/12 feet = 5 - 41/12 = 60/12 - 41/12 = 19/12 = 1 7/12 feet
The seedling grew 1 7/12 feet during the 2nd year.