(1)9.34-(2.34+0.49)=9.34-2.34-0.49=7-0.49=6.51;(2) 8 15 ×9- 2 15 ÷ 1 9 = 8 15 ×9- 2 15 ×9=( 8 15 - 2 15 )×9= 2 5 ×9=3.6;(3)(0.8-0.91÷2.6)×2.8 =(0.8-0.35)×2.8=0.45×2.8=1.26; (4)3060÷15-2.5×1.04=204-2.6=201.4.