Đáp án+Giải thích các bước giải:
$a)5,3-(-5,1)+(-5,3)+4,9\\=5,3+5,1-5,3+4,9\\=(5,3-5,3)+(5,1+4,9)\\=10$
$b)(2,7-51,4)-(48,6-7,3)\\=2,7-51,4-48,6+7,3\\=(2,7+7,3)+(-51,4-48,6)\\=10-100\\=-90$
$c)2.5 .(-0,124)+10,124.2,5\\=2,5.(-0,124+10,124)\\=2,5.10\\=25$