Bonjour,
1/2 + 5/3 × 1/3 =
1/2 +5/9
= (1/2*9/9) +(5*9*2/2)
= 9/18 +10/18 = 19/18
2/5 + 3/10 - 3/4 × 1/5 =
2/5 +3/10 -3/20
= (2/5*4/4) +(3/10*2/2) -3/20
= 8/20 +6/20 -3/20
= 11/20
( 3/7 + 5/14 )×( 3/11 + 1/22 ) =
(3/7*2/2 +5/14) * (3/11*2/2 +1/22)
= ( 6/14 +5/14) *( 6/22+1/22
= 11/14 *7/22
= 77/ 308
= 11/44
13/14 - [ 5/8 + 3/2 × 1/8 ] =
13/14 -[5/8 +3/16]
= 13/14 - [ 5/8*2/2 +3/16]
= 13/14 - [10/16 +3/16]
= 13/14 -7/16
= (13/14*16/16) -(7/16 *14/14)
= 208/224 - 98/224
= 110/224
= 55/ 112
6/7 × 14/24 + 3/2 =
84/168 +3/2
= 42/84 +3/2
= 21/42+3/2
= 1/2+3/2
= 3/2
bonjour
A) 1/2 + 5/3 × 1/3 = multiplication d'abord
1/2 + (5 x 1) / 3 x 3) =
1/2 + 5/9 = dénominateur commun 18
9/18 + 10/18 =
19/18
B) 2/5 + 3/10 - 3/4 × 1/5 = multiplication d'abord
2/5 + 3/10 - 3/20 = dénominateur commun 20
8/20 + 6/20 - 3/20 =
14/20 - 3/20 =
11/20
C) ( 3/7 + 5/14 )×( 3/11 + 1/22 ) = d'abord les ( )
(6/14 + 5/14) x (6/22 + 1/22) =
( 11/14) x (7/22) =
(11 x 7) / (14 x 22) = on simplifie par 7
(11 x 1) / (2 x 22) = on simplifie par 11
(1 x 1) / (2 x 2) =
1/4
D)
13/14 - [ 5/8 + 3/2 × 1/8 ] = crochet en premier, dans le crochet
on commence par la multiplication
13/14 - [5/8 + 3/16] = dénominateur 16
13/14 - [5/8 + 3/16] =
13/14 - [10/16 + 3/16] =
13/14 - 13/16 = dénominateur commun 14 x 8 = 16 x 7 = 112
(13 x 8) / 112 - (13 x 7) / 112 =
104 / 112 - 91 / 112 =
(104 - 91)/12 =
13/112
E) 6/7 × 14/24 + 3/2 = multiplication d'abord
(6 x 14)/(7 x 24) + 3/2 = on simplifie par 7
(6 x 2) /(1 x 24) + 3/2 = on simplifie par 6
(1 x 2)/(1 + 4) + 3/2 = on simplifie par 2
1/2 + 3/2 =
4/2 =
2
