[section 3][integers]

(1.)  -3 + 6                         here is the problem

result:  3

(2.)   2 + (-5)                       here is the problem

result:  -3

(3.)   (-3) + 7                         here is the problem

result:  4

(4.)   (-9) + 8                       here is the problem

result: -1

(5.)   (-7) + (-2)                        here is the problem

result:  -9

(6.)   -8 + 3                           here is the problem

result:  -5

(7.)  0 + (-9)                      here is the problem

result:  -9

(8.)   9 + (-6)                          here is the problem

result:  3

(9.)  8 + (-7)                       here is the problem

result:  1

(10.)   8.6 + (-3.7)               here is the problem

result:  4.9

(11.)   5 - (-9)                 here is the problem

=    5 + 9              minus minus means plus

result:  14

(12.)    6 - 11                here is the problem

=   -5                        subtract

result:  -5

(13.)     -10 - 10                 here is the problem

=   -20                         subtract

result:  -20

(14.)    -4 - 5                     here is the problem

=   -9                         subtract

result:  -9

(15.)   -6 - (-4)                here is the problem

=   -6 + 4              minus minus means plus

result:  -2

(16.)   9 - 9              here is the problem

=   0                     subtract

result:  0

(17.)   0 - 7.8             here is the problem

=   -7.8                   subtract

result:  -7.8

(18.)  6.7 - (-12.3)             here is the problem

=   6.7 + 12.3           minus minus means plus

result:  19

(19.)   -8 - 4                     here is the problem

=   -12                        subtract

result:  -12

(20.)  16 - (-15)               here is the problem

=   16 + 15           minus minus means plus