Đáp án+Giải thích các bước giải:
$\\a)\left({\dfrac{617}{191}+\dfrac{29}{33}-\dfrac{115}{117}}\right).\left({\dfrac14-\dfrac15-\dfrac1{20}}\right)\\=\left({\dfrac{617}{191}+\dfrac{29}{33}-\dfrac{115}{117}}\right).\left({\dfrac5{20}-\dfrac4{20}-\dfrac1{10}}\right)\\=\left({\dfrac{617}{191}+\dfrac{29}{33}-\dfrac{115}{117}}\right).0\\=0$
$\\b)\dfrac{12}5.\left({\dfrac{10}3-\dfrac5{12}}\right)\\=\dfrac{12}5.\left({\dfrac{40}{12}-\dfrac5{12}}\right)\\=\dfrac{12}5.\dfrac{35}{12}\\=7$
$\\c) 1,23-5,48+8,77-4,32\\= (1,23+8,77)+(-5,48-4,32)\\=10-9,8\\=0,2$
$\\d)7.0,25+9.0,25\\=0,25.(9+7)\\=0,25.16\\=4$