6. Aflati numărul necunoscut
a) (9 x 12 - 10 x 6 - a) + (127 + 36 : 4) = 213 x 9 + 3:
b) 194 x 3 + 200 - a = 493
c) (104 x 4 + 83 x 5) - a x 3 = 8 x 100 + 36:9
d) (138 x 5 - 21: 7 - 300 x 2) - 9 x 9 - rx 2 = 2
e) 40: 8 + 124 x 5 + g = 719;
f) (321 x 2 - 115 x 4) + 42: d = 180 + 2 x 4
g (143 - b - 4 x 8) + 3 x 6 : 2 = 9 x 2 + 5 x 10:
h) (6 x 4:3+ c): 9 = 32 : 8
e) (9 x 4: 6 x d) - 7 x 7 = 5 x 9:5-4;​