= chín phần hai 

1/3 + 5/2 + 10/6 = 4/12 + 30/12 + 20/12 = 54/12 = 27/6

1/3 + 5/2 + 10/6 =

Quy đồng :

1/3 = 1/3 x 2 = 2/6

5/2 = 5/2 x 3 = 15/6

10/6 giữ nguyên

=> 2/6 + 15/6 + 10/6 = 27/6

Vậy : 1/3 + 5/2 + 10/6 = 27/6

\(\frac{1}{2}+-\frac{1}{5}+-\frac{5}{7}+\frac{1}{6}-\frac{3}{35}+\frac{1}{3}+\frac{1}{41}=\frac{1}{41}\)

1/41 giai ra dai nam cu rut gon roi quy dong

\(\frac{1}{2}+\left(-\frac{1}{5}\right)+\left(-\frac{5}{7}\right)+\frac{1}{6}+\left(-\frac{3}{35}\right)+\frac{1}{3}+\frac{1}{41}\)

\(=\left(\frac{1}{2}+\frac{1}{6}+\frac{1}{3}\right)+\left[\left(\frac{-1}{5}\right)+\left(-\frac{5}{7}\right)+\left(-\frac{3}{35}\right)\right]+\frac{1}{41}\)

\(=1+\left(-1\right)+\frac{1}{41}\)

=0+1/41=1/41

có phải đề là:

\(\frac{1}{2}\)+\(\frac{2}{3}\)+\(\frac{3}{4}\)+\(\frac{4}{5}\)+\(\frac{3.99}{100}\)không bạn

I Love you mik nghĩ bn nên đọc kĩ đề hơn .Cộng 3 chấm là cộng ... mà chứ k phải 3.99

ừm hứm

3/4+-5/12+6/24

=18/24-10/24+6/24=14/24=7/12

\(\dfrac{3}{4}+\left(-\dfrac{5}{12}\right)+\dfrac{6}{24}=\dfrac{18}{24}+\dfrac{-10}{24}+\dfrac{6}{24}=\dfrac{14}{24}=\dfrac{7}{12}\)

7/12

\(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+...+\dfrac{1}{99\cdot100}\)

\(=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

\(=1-\dfrac{1}{100}\)

\(=\dfrac{99}{100}\)

=6/1=6

ht

\(\frac{9}{15}+\frac{3}{5}=\frac{3}{5}+\frac{3}{5}=\frac{6}{5}\)

\(\frac{9}{15}+\frac{3}{5}=?\)

\(\frac{9}{15}+\frac{3}{5}=\frac{45}{75}+\frac{45}{75}\)

\(=\frac{90}{75}\)

Rút gọn ta được: \(\frac{90:3}{75:3}=\frac{30}{25}\Rightarrow\frac{30:5}{25:5}=\frac{6}{5}\)

Đáp số: \(\frac{6}{5}\)

Sáu phần năm

a 15/7"3/4