1- - =1-( ) +( - )= +
① + = ② ﹣ = ③ + = ④ ﹣ = ⑤ + =
⑥1+ = ⑦ + ﹣ = ⑧ ﹣ ⑨ + = ⑩1﹣ + =
① - +
② -( - )
③ - + -
④ + +
⑤7-( - )
⑥ + -