cho phan so 17/35 tim 1 so nao do sao cho khi cong tu so voi so day va giu  nguyen mau so thi  co phan so moi co gia tri bang 5/7

Cho phan so a/b co gia tri bang 3/4 neu giam mau so di 12 don vi va giu nguyen tu so thi duoc phan so moi co gia tri bang 6/7 tim gia tri cua phan so a/b

cho a/b bang 4/5 neu cong them 33 vao tu so va giu nguyen mau son thi duoc phan so moi la 25/41

ai nhanh minh tick 

minh can gap chieu nay nop roi xin cac ban giup minh

GIA TRI 1 PHAN SO THAY DOI THE NAO NEU TA THEM VAO TS VA GIU NGUYEN MS

GIA TRI 1 PHAN SO THAY DOI NHU THE NAO NEU TA THEM VAO TS 1 SO BANG MS VA GIU NGUYEN MS

a Gia tri mot phan so se thay doi nhu the nao neu ta them vao tu so mot so bang mau so va giu nguyen mau so

b Gia tri mot phan so se thay doi nhu the nao neu ta them vao tu so mot so bang tu so va giu nguyen mau so

Tim mot phan so,biet rang neu them 2 vao tu so va giu nguyen mau so thi duoc phan so co gia tri bang 1;neu them 3vao mau so va giu nguyen tu so thi douc phan so co gia tri bang 1/2?

cho phan so 55/77.tim1so biet rang sao cho dem mau cua phan so do cho chu di so do va giu nguyen tu so thi duoc phan so moi co gia tri bang 4/5

cho phan so 5/11 .Hay tim mot so nao do de khi cong cung so do vao tu so va mau so cua phan so da cho thi duoc mot phan so co gia tri bang 2/3

Cho phân số -5/9 

a) hoi phai cong them vao mau va bot di vao tu cho cung mot so nao e duoc phan so moi co gia ri bang phanso -7/12

b) hay tim mot so nao sao cho khi cong so do vao tu hthem vao mau hai lan so do thi duoc phan so co gia tri bang 1/3