It is 2 and seven- tenths because you have to turn two-fifths into tenths to match 1 and seven-tenths so then you have 4 4/10 - 1 7/10 you have to regroup so you take 1 whole out of the 4 while equals 10 so you have 3 14/10. Then you can subtract 3 14/10 - 1 7/10 and get 2 7/10. Hope this helps:)
