a = ( 12 + 12 ) : 6 + 12 : ( 12 - 10 ) =
a = 24 : 6 + 12 : ( 12- 10 ) =
a = 24 : 6 + 12 : 2 =
a = 4 + 12 : 2 =
a = 4 + 6
a = 10
b = 11 + 10 : ( 11- 6 : 6 ) - 10 =
b = 11 + 10 : ( 11 - 1 ) - 10 =
b = 11 + 10 : 10 - 10 =
b = 11 + 1 - 10 =
b = 12 - 10
b = 2