1. Use 2 / 9, 3 / 5 and a number to form a proportional expression, which may be () (not innumerable)

1. Use 2 / 9, 3 / 5 and a number to form a proportional expression, which may be () (not innumerable)

1. Form a proportion formula with 9,3,2 / 5 and a number, which may be (6 / 5 or 2 / 15). (not innumerable)