1) 6 + 4 9/11 = 6 44/11

2) 1/14 + 9 3/7 = 9 3/7 + 1/14 = 65/7 + 1/14 = (130/14) + 1/14 = 131/14

3) 5/7 + 3 1/4 = 5/7 + 13/4 = 20/28 + 91/28 = 111/28