32 x 38 = 30 x 40 + 2 x 8
34 x 36 = 30 x 40 + 4 x 6
56 x 54 = 50 x 60 + 6 x 4

73 x 77 = 70 x 80 + 3 x 7

and so on?

Verify and generalise if possible.