1.121*[100（1/121）]=121*100+1=12101
2.提取公因数=2.75(2.7+6.3+1)=27.5
3.都化为假分数=(13/2)*(7/2)*(3/5)=273/20
4.化简,约分=(25/8)*(8/5)-(14/9)*(9/7)=5-2=3
5.化简,提取公因数=2000*(21/5)-(16/5)*2000=2000[(21/5)-(16/5)]=2000
6.化简：（3/8）*[(7/2)-(5/2)*(4/5)]*(4/9)=(3/8)*[(7/2)-2)]*(4/9)= (3/8)*(3/2)*(4/9)=1/4
7.=(7/10)*[(3/4)-(3/16)]=(7/10)*(9/16)=63/160