数学1入門1-3想定問題4

1．

$$
(+3)+(-8) = \\
(-2) + (-5) = \\
(+7) +(-9) = \\
(+6) -(-3) = \\
(+4)+(-2)-(+8) =\\
3-5+6-1=\\
-5-4-2-1=\\
$$