Giúp mình với cảm ơn mng

a, ( 4/9 + 14/9 ) + (-12/7 - 9/7) + 1/6 
= 18/9 -21/7 + 1/6 
= 2-3+1/6 
= -1+ 1/6
=- 6/6 + 1/6 = -5/6 
b,  6,3 . 3,8 -6,3 . 4,8 - 3,3 

 = 6,3 . ( 3,8 - 4,8) -3,3 

= 6,3 . ( -1 ) - 3,3 
= -6,3 - 3,3 

= -9,6
c, 11/12 ( 25% - 5/6 ) - ( -2) ³ .7/8
= 11/12 ( 1/4 - 5/6 ) - (-8) . 7/8
= 11/12 ( 3/12 -10/12 ) - ( -7) 
= 11/12 . ( -7/12 ) +7 
= - 77/144 + 7 
= -77/144 = 1008/144= 931/144 

d, 0,8 - 2/9 - 4/5 + ( -2024)^0 

= 4/5 - 2/9 - 4/5+1 
= ( 4/5 - 4/5 ) -2/9+1 
= 0 - 2/9+1

= 1 - 2/9 
= 9/9 - 2/9
= 7/9
e, (-2)³ . ( -3/4) - ( 3/8 - 2 1/6 ) ; 21,5
= -8. ( -3/4) - ( 3/8 - 13/6) : 43/2 
= 6 - ( 9/24) - 52/24) : 43/2 
= 6 - ( - 43/24 . 2/43) 
= 6 - ( - 1/12)= 6+ 1/12 = 72/12 + 1/12 = =  73/12