Question

−15,23−(−34,66)−24,61−(−4,53)+(−81,67)

Answer 1

$\tt\displaystyle -15,23-(-34,66)-24,61-(-4,53)+(-81,67)=\\=-15,23+34,66-24,61+4,53-81,67=\\=19,43-24,61+4,53-81,67=\\=-5,18+4,53-81,67=\\=-0,65-81,67=\\=\bold{-82,32}$