(15 1/3-8 5/18)×2 4/7÷6 1/21-2 5/8=

(15 1/3 - 8 5/18) * 2 4/7 : 6 1/21 - 2 5/8 = 3/8

1) 15 1/3 - 8 5/18 = 15 6/18 - 8 5/18 = 7 1/18
2) 7 1/18 * 2 4/7 = 127/18 * 18/7 = 127/7
3) 127/7 : 6 1/21 = 127/7 : 127/21 = 127/7 * 21/127 = 21/7 = 3
4) 3 - 2 5/8 = 2 8/8 - 2 5/8 = 3/8