Bonsoir,
520/390
leur diviseur commun:
2*5*13 = 130
520/130 =4
390/130= 3
520/130 = 4/3
52/ 390
diviseur commun: 2*13 = 26
=>2/ 15
26/39
diviseur commun: 13
=> 2/3
1040/ 780
1040 = 2*520
780 = 2*390
diviseur commun:
2*5*13 = 130
130*2 = 260
1040/260 = 4
780/260= 3
1040/ 780 = 4/3
exercice 57
224/2 = 112
112/2 =56
56/2 = 28
28/2= 14
14/2 = 7
=> 2*2*2*2*2*7
280/2 =140
140/2 70
70/2 =35
35/5 =7
=> 2*2*2*5*7
En commun:
2*2*2*2*2*7
2*2*2*5*7
2*2*2 *7 = 56
224/ 56 = 4
280/56= 5
224 / 280 = 4/5
