Răspuns :
a)
3 × 4 = 12
12 - 3 = 9
b)
21 ÷ 7 = 3
15 ÷ 5 = 3
Sper ca am ajutat!
a). 3/4 = 9/12 ⇒ I. (1)... 12/4 =9/3 ; (2)... 3/9 = 4/12 ; 4/3 = 12/9 ;
II. (1)... 3*2/4=9*2/12 ⇔ 6/4=18/12
(2)... 3/4:4=9/12:4 ⇔ 3/1= 9/3
(3)... 3*5/4*5=9/12 ⇔ 15/20=9/12
b). 7/5=21/15 ⇒ I. (1)... 15/5=21/7 ; (2)... 7/21=5/15 ; (3)... 5/7=15/21 ;
II. (1)... (7+5)/5=(21+15)/15 ⇔ 12/5=36/15
(2)... 7.(7-5)=21/(21-15) ⇔ 7/2 = 21/6
(3)... (7+5)/(7-5)=(21+15)/(21-15) ⇔ 12/2=36/6
II. (1)... 3*2/4=9*2/12 ⇔ 6/4=18/12
(2)... 3/4:4=9/12:4 ⇔ 3/1= 9/3
(3)... 3*5/4*5=9/12 ⇔ 15/20=9/12
b). 7/5=21/15 ⇒ I. (1)... 15/5=21/7 ; (2)... 7/21=5/15 ; (3)... 5/7=15/21 ;
II. (1)... (7+5)/5=(21+15)/15 ⇔ 12/5=36/15
(2)... 7.(7-5)=21/(21-15) ⇔ 7/2 = 21/6
(3)... (7+5)/(7-5)=(21+15)/(21-15) ⇔ 12/2=36/6