Tính

1) 1/3 - [ - 5/4 - + 4/3 - 1/4 ) ] 
2) 2/–5 + –3/7 + –14/10 - 3/–7 
3) ( - 2/5 )² . 6/113 + (2/5)². 7/13 
4) ( –2/3 )² . 3/7 + (2/3)².2 ⁴/⁷ 
5) 16 ²/⁷ : ( –3/5 ) - 28 ²/⁷ :  (​​– 3/5)