28 - 19 = 945 - 18 = 27
28 - 19 =28 - 20 + 1 = 8 + 1 = 9
45 - 18 =45 - 20 - 18 + 2 = 25 - 18 + 2 = 7 + 2 = 27
28 - 19 = 9
Второй способ:45 - 18 = 27
28 - 19 =
28 - 20 + 1 = 8 + 1 = 9
45 - 18 =
45 - 20 - 18 + 2 = 25 - 18 + 2 = 7 + 2 = 27