78×12−12×38 38×0.6÷34−23 5×13−15÷512
①0.96×516÷15 ②49÷4+4÷49 ③2019×20192020
④1784×13+1384×25 ⑤(320+2.1)×47÷0.9 ⑥0.5+156÷(0.75+1920)
2.3×1.5+4.5÷0.75 49÷[45−(15+13)] (7.5+2.5)÷0.25