w) (500-14) x 10: [680 (635-a)] x 5 = 405
x) [136+ (42 xax8-905) - 27 x 80] : 5 = 19
y) [(163 x 4 + a): 100 + 182]: 2+20 x 5 = 196
z) (99:9+7) x 10+ [72+ (a - 2 x 44 x 3)] + 1000 = 1355​