Use each of the numbers 2, 3, 7 and 8 and brackets () and the signs +, - , x, ÷ to make each of the numbers from 20 to 50. you can use each number just once in each calculation.

(8 * 2) + (7 - 3) = 16 + 4 = 20
(8 * 3) + 7 - 8 = 24 - 1 = 23
(8 * 3) - 7 + 8 = 24 + 1 = 25
(7 * 3) + (8 - 2) = 21 + 6 = 27
(8 * 3) + (7 - 2) = 24 + 5 = 29
8/2 * 7 + 3 = 4 * 7 + 3 = 28 + 3 = 31
(7 * 3) + (8 * 2) = 21 + 16 = 37
(8 * 3) + (7 * 2) = 24 + 14 = 38
8/2 * (7 + 3) = 4 * 10 = 40
(8 * 7) - (3 * 2) = 56 - 6 = 50

well...there is some of them :)

Try a or d, hope that