Mathématiques

Question

Bonjkur , je suis en 5eme etj ais un DM a rendre mqis jy comprend riienn :( Svp HELP ! <3

Calculer chaque expression sachant que ;

M= 1 neuvieme ; N= 2 tiers ; P=5 sur 18

a) m+n b) p -m c) np.
----------------------------------------------
Exercice 2 ;

A =3 huitieme fois (4 neuvieme + 2 tiers)

B= 3huitieme fois 4 neuvieme + 2 tiers

C = 7 cinquieme fois ( 3 dixieme + 1 cinquieme)

D = 7 cinquieme fois 3 dixieme + 1 sur 5 .

Merci de votre aide ! ;)

1 Réponse

  • Calculer chaque expression sachant que :

    M = 1/9 ; N = 2/3 ; P = 5/18

    a) m + n
    1/9 + 5/18
    = 1 x 2 / 9 x 2 + 5/18
    = 2/18 + 5/18
    = 7/18

    b) p - m
    5/18 - 1/9
    = 5/18 - 1 x 2 / 9 x 2
    = 5/18 - 2/18
    = 3/18
    = 3 x 1 / 3 x 6
    = 1/6

    c) np
    2/3 x 5/18
    = 2 x 5
      3 x 18
    = 10/54
    = 2 x 5 / 2 x 27
    = 5/27
    ----------------------------------------------
    Exercice 2 ;

    A = 3/8 x (4/9 + 2/3)
    A = 3/8 x (4/9 + 2 x 3 / 3 x 3)
    A = 3/8 x (4/9 + 6/9)
    A = 3/8 x 10/9
    A = 3 x 10
           8 x 9
    A = 30/72
    A = 6 x 5 / 6 x 12
    A = 5/12

    B = 3/8 x 4/9 + 2/3
    B = 3 x 4 + 2/3
          8 x 9
    B = 12/72 + 2/3
    B = 12/72 + 2 x 24 / 3 x 24
    B = 12/72 + 48/72
    B = 60/72
    B = 12 x 5 / 12 x 6
    B = 5/6

    C = 7/5 x (3/10 + 1/5)
    C = 7/5 x (3/10 + 1 x 2 / 5 x 2)
    C = 7/5 x (3/10 + 2/10)
    C = 7/5 x 5/10
    C = 7 x 5
          5 x 10
    C = 35/50
    C = 5 x 7 / 5 x 10
    C = 7/10

    D = 7/5 x 3/10 + 1/5

    D = 7 x 3 + 1/5
          5 x 10
    D = 21/50 + 1 x 10 / 5 x 10
    D = 21/50 + 10/50
    D = 31/50

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