96                 

cầu đời

96

Sai

Sai. Vì: \(98dm^2=0,98m^2\) 

Sai

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

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

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

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

\(=0\)

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

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

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

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

Ta có: \(A=\frac{97^{98}+1}{97^{99}+1}\Rightarrow97A=\frac{97^{99}+97}{97^{99}+1}=\frac{97^{99}+1+96}{97^{99}+1}=1+\frac{96}{97^{99}+1}\)

\(B=\frac{97^{97}+1}{97^{98}+1}\Rightarrow97B=\frac{97^{98}+97}{97^{98}+1}=\frac{97^{98}+1+96}{97^{98}+1}=1+\frac{96}{97^{98}+1}\)

Vì \(\frac{96}{97^{99}+1}< \frac{96}{97^{98}+1}\Rightarrow1+\frac{96}{97^{99}+1}< 1+\frac{96}{97^{98}+1}\Rightarrow97A< 97B\Rightarrow A< B\)

Vậy A < B

Ta thấy A < 1 và 96 > 1 nên ta có:

            A <     97⁹⁸ + 1 + 96 / 97⁹⁹ + 1 + 96

      =>  A <     97⁹⁸ + 97 / 97⁹⁹ + 97

      =>  A <     97(97⁹⁷ + 1) / 97(97⁹⁸ + 1)

      =>  A <     97⁹⁷ + 1 / 97⁹⁸ + 1 = B

      => A < B

A<B

nhanh và gọn, lẹ

98 - 97+96- 95 + ...+ 2-1

= ( 98- 97 ) + ...+ ( 2-1)

    có 49 cặp 

= 1+1+1...+1

     có 49 số

= 1 x 49 

= 49

câu trên mik chịu

= 49 

bn ko biết câu trên nên chỉ được 2 ^^

8.9.36+12.6.115-36.2.51

=(8.9).36+(12.6).115-(36.2).51

=72.36+72.115-72.51

=72.(36+115-51)

=72.100

=7200

98-97+96-95+.....+2-1

=(98-97)+(96-95)+......+(2-1)

=1+1+1+1+1+1+......+1+1(49 số 1)

=49

(-99)+ (-98) + (-97) +... + 97 + 98 + 99 + 100

= (-99 +99) + (-98 + 98) + (-97+97) +... + (-2+2) + (-1 + 1) + 100

= 0 + 0 + 0 + ... + 0 + 0 + 100

=100

=[(-99)+99]+[(-98)+98]+[(-97)+97]+..+100

=0+0+0+...+100=100