（+16）+（-30）-（-14）=16-30+14=0
-40-25-（-19）+（-24）= -40 -25+19-24 = -70
11又1/2-1又3/4-1又1/4+4又1/2 = (11又1/2+4又1/2)-(1又3/4+1又1/4) = 16 - 3 =13