Répondre :
Bonjour;
a. 1/20 + 4/5
=1/20+4/5*4/4
= 1/20+16/20
= 17/20
b. 7/9 + 2/81
=7/9*9/9 +2/81
= 63/81+2/81
= 65/81
c. 5/6 + 1/30
=5/6*5/5 +1/30
=25/30+1/30
=26/30
d. 19/28 + 3/7
= 19/28 +3/7*4/4
= 19/28 +12/28
= 31/38
Bonjour;
a. 1/20 + 4/5
=1/20+4/5*4/4
= 1/20+16/20
= 17/20
b. 7/9 + 2/81
=7/9*9/9 +2/81
= 63/81+2/81
= 65/81
c. 5/6 + 1/30
=5/6*5/5 +1/30
=25/30+1/30
=26/30
d. 19/28 + 3/7
= 19/28 +3/7*4/4
= 19/28 +12/28
= 31/38