They are:
54 x 1
54 x 2
54 x 3
54 x 4
54 x 5
54 x 6
54 x 7
54 x 8
54 x 9
and
54 x 10
MmsMms
54, 108, 162 and so on.
2.
The numbers are 8 and -54 Check: 8+(-54) = -46 and 8*-54 = -432
33
54
-69
Decimal
54 to the nearest ten is 50
64, 640, 6400, 64000, 640000, 6400000, 64000000, 640000000, 6400000000 and 64000000000 are ten multiples (not multiplies!).
1, 2, 3, 6, 9, 18, 27, 54 (1 x 54, 2 x 27, 3 x 18, 6 x 9).
A ten-minute call will cost $2.52 in total. 1 x 54 = 54 and 9 x 22 = 198, 54+198 = 252