tính B

\(1+\frac{99}{98}-\frac{98}{97}+\frac{1}{97.98}\)

\(=1+1+\frac{1}{98}-\left(1+\frac{1}{97}\right)+\frac{1}{97}-\frac{1}{98}\)

\(=1+1+\frac{1}{98}-1-\frac{1}{97}+\frac{1}{97}-\frac{1}{98}\)

\(=1+1-1\)

\(=1\)

thank

\(\frac{99}{98}-\frac{98}{97}+\frac{1}{97\times98}\)

\(=\left(1+\frac{1}{98}\right)-\left(1+\frac{1}{97}\right)+\frac{1}{97\times98}\)

\(=\frac{1}{98}-\frac{1}{97}+\frac{1}{97\times98}\)

\(=\frac{-1}{97\times98}+\frac{1}{97\times98}\)

\(=0\)

\(\frac{99}{98}-\frac{98}{97}+\frac{1}{97X98}=\left(1+\frac{1}{98}\right)-\left(1+\frac{1}{97}\right)+\frac{1}{97X98}\)

\(=\frac{1}{97X98}-\frac{1}{97X98}=0\)

Nguyễn tuấn thảo ơi người ta mới lớp 5 bạn thêm -1 vào chi ? :)

        \(\frac{99}{98}\)- \(\frac{98}{97}\)+ \(\frac{1}{97}\)*  98

=\(\frac{9603}{9506}\)-\(\frac{9604}{9506}\)+ \(\frac{98}{9506}\)* \(\frac{98}{1}\)

            -Sai đề rồi bạn nhé!

Trả lời

99/98-98/97+1/97.98

=9603/9506-9604/9506+98/9506.98/1

=97/9506.98

=9506/9506

=1

Pé Shusi ơi: 

        * Nhân chia trước cộng trừ sau nhé!

                                   # Kiều

đề :

= 1/100 - (1 / 100.99 +1/99.98 + ...+ 1/3.2 +1/2.1 ) 

=1/100 - (1 /1.2 +1/ 2.3 +...+ 1/ 98.99 +1 / 99.100)

=1/100 -( 1- 1/ 2 +1/2 -1/3 +...+1/98 -1/99 +1/99 -1/100)

=1/100 - ( 1- 1/100)

=1/100 - 99 /100

= -98/100

= -49 /50

(91-99+98)-(-99+98)=91-99+98+99-98=91

(99-98+97)-(99+97+98)=99-98+97-99-97-98=(-98)*2=-196

1. (91 - 99 + 98) - (-99 + 98)

= 91 - 99 + 98 + 99 - 98

= (-99 + 99) + (98 - 98) + 91

= 0 + 0 + 91

= 91

2. (99 - 98 + 97) - (99 + 97 + 98)

= 99 - 98 + 97 - 99 - 97 - 98

= (99 - 99) + (97 - 97) + (-98 - 98)

= 0 + 0 + (-196)

= -196