计算：①（-7）+（-78）-（-3）-（-23）；②−15−2−(−25)−(+315)；③|-738+412|+（1814）+|-6-12|；④−235−(+74)−(−612)+(−710)−(−0.3)．

Question

计算：
①（-7）+（-78）-（-3）-（-23）；
②−(1)/(5)−2−(−(2)/(5))−(+3(1)/(5))；   
③|-7(3)/(8)+4(1)/(2)|+（18(1)/(4)）+|-6-(1)/(2)|；
④−2(3)/(5)−(+(7)/(4))−(−6(1)/(2))+(−(7)/(10))−(−0.3)．

Answer 1

①（-7）+（-78）-（-3）-（-23）
=-7-78+3+23
=-85+26
=-59；

②−(1)/(5)−2−(−(2)/(5))−(+3(1)/(5))   
=（-(1)/(5)+(2)/(5)-3(1)/(5)）-2
=-3-2
=-5；

③|-7(3)/(8)+4(1)/(2)|+（18(1)/(4)）+|-6-(1)/(2)|
=7(3)/(8)-4(1)/(2)+18(1)/(4)+6+(1)/(2)
=（7(3)/(8)+18(1)/(4)）+（(1)/(2)-4(1)/(2)）+6
=25(5)/(8)-4+6
=27(5)/(8)；

④−2(3)/(5)−(+(7)/(4))−(−6(1)/(2))+(−(7)/(10))−(−0.3)
=-2(3)/(5)+（-(7)/(10)+(3)/(10)）+（-1(3)/(4)+6(1)/(2)）
=-2(3)/(5)-(2)/(5)+4(3)/(4)
=