Tính nhanh

Tính nhanh:
a,4/9 + (2/5 + 5/9) b,7/15 - (4/7 - 6/13)
c,7/6 - 1/3 - 1/2 + 5/6. d,2/5 × 1/4 + 3/4 ×2/5
e,6/11 : 2/3 + 5/11 : 2/3
g,29/12 : 1/2 -5/12 : 1/2 - 1/2
h,6/7 × 5/8 7/3 × 7/6 × 8/5