2 x 10 = 20
5 + 50 = 55
20 x 75 = 1500
50 + 55 = 105
1500 + 105 = 1605

75 / 5 = 15
50 - 15 = 35
10 x 35 = 350
50 / 2 = 25
350 - 25 = 325