986÷34×138-2005 =(986+34-34)÷34×138-2005 =(1020÷34-34÷34)×138-2005 =[(10×3×34)÷34-1]×138-2005 =(30-1)×(70-1)×2-2005 =(2100-70-30+1)×2-2005 =2001×2-2001-4 =2001-4 =1997
