1) (6x9)-(7x6) = 54-42 = 12
2)axb = 24
bxb = c
c-18 = 36 ⇒ c = 36
bxb = 18 ⇒ b = 36:2 = 16
axb = 24 ⇒ a = (16:2) = 8 ⇒ 24:8 = 3 deci a = 3
3)30 - 25 = 5 ⇔ 6 x 5 = 30
81 - 74 = 7 ⇔ 6 x 7 = 42
99 - 91 = 8 ⇔ 6 x 8 = 48
73 - 63= 10 ⇔ 6 x 10 = 60
100 - 99 = 1 ⇔ 6 x 1 = 6
4)8 x 6 = 48 ↔ 100 - 48 = 52
5)(9x6)+(8x5) = 54 + 40 = 94
6)(5x6)x2 = 30 x 2 = 60
(8x5)x2 = 40 x 2 = 80
(2x5)x3 = 10 x 3 = 30
(2x4)x5 = 8 x 5 = 40
7)6 x 2 = 12 ⇆ 5 x 3 = 15 → 12 + 15 = 27
8)6x3=9x2 (A)
85-29=5x9 (F)
32+19=10x4 (F)
6x5=72-42 (A)
40+8=6x8 (A)
6x4=8x3 (A)