Bonjour tout le monde, j'ai quelques exercices de math et j'aimerai savoir si j'ai juste, merci

A)(3+12)+(48-27)                          
=3+4x3+16x3-9x3
=3+4x3+16x3-9x3        
=3+23+4x3-33
= 43.

B)(2+8)+18
=2+4x2+9x2
=2+4x2+9x2
=2+22+32
= 62.

C)20+5
= 4x5 +5
=4x5+5
=25+5
=350.

D) 20 x 5
=100
=10.

E) (2+8)x18
=(2+4x2)x18
=(2+2x2)x9x2
=32x9x2
=32x32
=92.

F)(3+12)(48+27)
=(3+3x4)(16x3-9x3)
=(3+3x4)(16x3-9x3)
=(3+23)(43-33)
=33x13
=33.

G)98+36-8
=(14x7)+(9x4)-(4x2)
=(14x7)+(29)-(22)
=(7x2x7)+6-4
=(7x2x7)+2
La je suis bloquée

H)75-108+12
=3x25-3x36+3x4
=3x25-3x36+3x4
=53-63+23
=13.

I)24-96+354
=6x4-6x16+36x9
=6x4-6x16+36x9
=26-46+3x36
=76.

          .le signe / réprèsente les divisions

J)2/33-1/418+2/52-1/412
=2/33-1/46x3+2/52-1/43x4
=2/3-1/4x33+2/52-1/4x23
=2/33-3/43+2/52-2/43
=8/123-9/123-6/123+2/42
=-7/123+2/42.

K)(3/4)-1/212+427-2(3/16)
=(3/4)-1/23x4+47x3-23/16)
=3/2-1/2x23+47x3-23/4
=3/2-1/2x23+47x3-(23)/4
=(23)/2x23+471(13)/4
=3/2-(1-4)/23+8/23-(13)/4
=(4/2)2-(13)/4  

L)(3/4)5-(1/3)28+(2/3)7-(1/4)25
=(3/4)5-(1/3)4x7+(2/3)7-(1/4)9x5
=(3/4)5-(2/3)7+(3x4)5
=0

M)(2/3)3-(1/4)18+(2/5)2-(1/4)12
=(2/3)3-(1/4)6x3+(2/5)2-(1/4)4x3
=(2/3)3-(1/4)6x3+(2/5)2-(1/4)4x3
=(2/3)3-(1/4)6x3+(2/5)2-(1/4)x3
Et ben la je suis bloquée

N) 12-27-48
=3x4-9x3-3x16
=3x4-9x3-3x16
=23-33-44
= -53

Merci d'avence pour votre aide, merci