4) 13 1/2 • 1 1/2÷2 1/4 = 27/2 • 3/2 ÷ 9/4 = 27/2 • 3/2 • 4/9 = 3 • 3/2 • 2 = 3 • 3 = 9
6) 13/14÷1 4/21 ÷ 13/5 = 13/14 ÷ 25/21 • 5/13 = 1/14 • 21/25 • 5 = 1/2 • 3/5 = 3/10 = 0.3
8) 2 16/19×2 1/9÷3 3/8 = 54/19 • 19/9 ÷ 27/8 = 6 • 8/27 = 2 • 8/9 = 16/9 = 1 7/9