Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(1+\frac{2}{3}-\frac{3}{5}+\frac{4}{5}=\frac{5}{3}-\frac{3}{5}+\frac{4}{5}=\frac{25}{15}-\frac{9}{15}+\frac{12}{15}=\frac{25-9+12}{15}=\frac{28}{15}\)
Tích cho mk nha bn!!!!!!!! ^_^
vậy ta quy đòng chị viết tắt nhá
1/3=15/45 ; 2/15=6/45. Sau khi em quy đồng xong thì cộng vào
15/45+6/45=21/45
xong rùi nhớ cho chị nha=)
a) $\frac{1}{6} + \frac{3}{2} + \frac{1}{2} = \frac{1}{6} + \left( {\frac{3}{2} + \frac{1}{2}} \right) = \frac{1}{6} + \frac{4}{2} = \frac{1}{6} + \frac{{12}}{6} = \frac{{13}}{6}$
b) $\frac{3}{8} + \frac{1}{2} + \frac{1}{8} = \left( {\frac{3}{8} + \frac{1}{8}} \right) + \frac{1}{2} = \frac{1}{2} + \frac{1}{2} = \frac{2}{2} = 1$
c) $\frac{2}{5} + \frac{6}{{10}} + \frac{3}{5} = \frac{2}{5} + \frac{3}{5} + \frac{3}{5} = \frac{{2 + 3 + 3}}{5} = \frac{8}{5}$
\(\frac{8}{15}+\frac{16}{30}+\frac{3}{5}+\frac{9}{10}+2\frac{3}{5}\)
\(=\frac{8}{15}+\frac{16}{30}+\frac{3}{5}+\frac{9}{10}+\frac{13}{5}\)
\(=\frac{16+16+18+27+78}{30}\)
\(=\frac{155}{30}\)
\(=\frac{31}{6}\)
Hc tốt #
\(\frac{8}{15}\)+\(\frac{16}{30}\)+\(\frac{3}{5}\)+\(\frac{9}{10}\)+2\(\frac{3}{5}\)
=\(\frac{16}{30}\)+\(\frac{16}{30}\)+\(\frac{18}{30}\)+\(\frac{27}{30}\)+\(\frac{13}{5}\)
=\(\frac{16+16+18+27}{30}\)+\(\frac{78}{30}\)
=\(\frac{77}{30}\)+\(\frac{78}{30}\)= \(\frac{155}{30}\)
\(S=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\)
\(S=1-\frac{1}{9}=\frac{8}{9}\)
câu 2:
A = 1/1*2 + 1/2*3 + 1/3*4 + ... + 1/98*99 + 1/99*100
A = 2-1/1*2 + 3-2/2*3 + 4-3/3*4 + ... + 99-98/98*99 + 100-99/99*100
A = 2/1*2 - 1/ 1*2 + 3/2*3 - 2/2*3 + 4/ 3*4 -3/3*4 +...+ 99/98*99 - 98/98*99 + 100/99*100 - 99/99*100
A = 1 - 1/ 100
A = 99 / 100
phần 2 mk ko =bít
bài 1, 3 mk ko bít
\(\frac{8}{2}+\frac{1}{3}\)
\(=\frac{24}{6}+\frac{2}{6}\)
\(=\frac{26}{6}=\frac{13}{3}\)
\(\Rightarrow\)
\(\text{Trả lời : }\)
\(\frac{8}{2}+\frac{1}{3}=\frac{24}{6}+\frac{2}{6}=\frac{26}{6}=\frac{13}{3}\)
\(\text{Chúc bạn học tốt ! }\)