342. 1) 11 5/7 × 4 4/11 - 4 4/11 × 6 5/7=

48/11(82/7-47/7)=48/11 × 35/7=240/11=21 9/11

2) 3 1/3 ×15/12/13 - 3 1/3 × 6 12/13=

10/3(15 12/13 - 6 12/13) 10/3 × 9 =30

382. 1) 1 5/12 × 3/34 + 1 5/12 × 1 31/34=

17/12(3/34 + 1 31/34)=17/12 ×2=17/6=2 5/6

2) 10 2/3 × 2 2/5 - 2 2/5 × 5 1/2=

12/5(32/3 - 11/2)=12/5(64/6 - 33/6)=

12/5 × 31/6 = 62/5=12 2/5