1 ) -10 + ( -7 ) + ( +10 ) + ( -5 ) =
= -7 -5
= -12
2 ) -11 + ( -4 ) + ( -8 ) + 21 =
= -11 - 4 - 8 + 21
= -15 - 8 + 21
= -23 + 21
= -2
3 ) -13 + ( +9 ) + ( -4 ) + ( -9 ) =
= -13 - 4
= -17
4 ) 7 - 11 + 14 =
= -4 + 14
= 10
5 ) 0 - ( +5 ) = -5
6 ) -3 - ( -6 ) =
= -3 + 6
= 3
7 ) +6 - ( +12 ) =
= - ( 12 - 6 )
= -6