99 + 99 x 99

= 99 + 9801

= 9900

Ủng hộ tíck mik nha !!! Xin đó ~~~~~

99+99x99= 9900

99 + 99 x 99

= 99 + 9801

= 9900

Các bạn nhé .

( * ) : 3 tích dành cho ...?

99+99-99x99:99 = 99

hk giỏi nhé

=999 nhé bạn 

=99

linh tinh

Ta có:99x99:99

=99x(99:99)

=99x1

=99

ai tích mình mình tích lại cho

99x99=99x9+99+99x9+99x.....

= 99x99=99 x 10+99x.......

= 99x99=99x100

= 99x99= 99x(99-10)

= > ... = 89

99x99=99x9+99+99x...

suy ra 99x99=99x(9+1+...)

suy ra 99x99=99x(10+...)

suy ra 99=10+...

suy ra ...=99-10

suy ra ....=89

99x99=99x9+99+99x89

Trả lời:

99 x 99 = 99 x 9 + 99 + 99 x 89

~ HOK TỐT ~

89

ミ★h̲̅Ọc̲̅ t̲̅Ốt̲̅★彡

_{thong minh bo duoi dau co dung khong ban khe thay doi khong ha  ban ge chua minh do ban 1+1=maythui deo biet}

bai nay la ngi trong oc la ra ai thong minh lam duoc 

99 x 99 = 9801

dễ lắm máy tính còn chậm hơn !

99 x 99 = 99 x 99 = 9801

Đáp án : 9801 .

Ta có :

\(A=\dfrac{1}{2.2}+\dfrac{1}{3.3}+\dfrac{1}{4.4}+.................+\dfrac{1}{99.99}+\dfrac{1}{100.100}\)

Ta thấy :

\(\dfrac{1}{2.2}< \dfrac{1}{1.2}\)

\(\dfrac{1}{3.3}< \dfrac{1}{2.3}\)

.............................

\(\dfrac{1}{99.99}< \dfrac{1}{98.99}\)

\(\dfrac{1}{100.100}< \dfrac{1}{99.100}\)

\(\Rightarrow A< \dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+..................+\dfrac{1}{98.99}+\dfrac{1}{99.100}\)

\(\Rightarrow A< \dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...........+\dfrac{1}{98}-\dfrac{1}{99}+\dfrac{1}{99}-\dfrac{1}{100}\)

\(\Rightarrow A< 1-\dfrac{1}{100}=\dfrac{99}{100}\)

\(\Rightarrow A< \dfrac{99}{100}\)

\(A=\dfrac{1}{2.2}+\dfrac{1}{3.3}+\dfrac{1}{4.4}+.....+\dfrac{1}{99.99}+\dfrac{1}{100.100}\)

\(A< \dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+.....+\dfrac{1}{98.99}+\dfrac{1}{99.100}\)
\(A< 1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+.....+\dfrac{1}{98}-\dfrac{1}{99}+\dfrac{1}{99}-\dfrac{1}{100}\)

\(A< 1-\dfrac{1}{100}\)

\(A< \dfrac{99}{100}\)

\(A< B\)