*TÌM THƯƠNG A:B BIẾT: A=9/1+8/2+7/3......+1/9 , B=1/2+1/3+1/4+......+1/10

Question

Đây là toán nâng cao lớp 7

Answer 1

A=10-1/1+10-2/2+10+3/3+......+10+9/9

A=10+1O/2+10/3+......10/9-(1/1+2/2+3/3+......+9/9)=10/2+10/3+.......+10/9+1

A=10(1/2+1/3+......+1/9+1/10)=10B

Vậy,A:B=10

Answer 2

A=10-1/1+10-2/2+10+3/3+......+10+9/9

A=10+1O/2+10/3+......10/9-(1/1+2/2+3/3+......+9/9)=10/2+10/3+.......+10/9+1

A=10(1/2+1/3+......+1/9+1/10)=10B

 Vậy,A:B=10