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bài 1:
\(\frac{6}{11}+\frac{1}{3}+\frac{5}{11}\)
\(=\left(\frac{6}{11}+\frac{5}{11}\right)+\frac{1}{3}\)
\(=\frac{11}{11}+\frac{1}{3}=1+\frac{1}{3}=\frac{3}{3}+\frac{1}{3}=\frac{4}{3}\)
bài 2:
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}\)
\(=\left(\frac{1}{2}+\frac{1}{20}\right)+\left(\frac{1}{6}+\frac{1}{12}\right)\)
\(=\frac{11}{20}+\frac{1}{4}=\frac{11}{20}+\frac{5}{20}=\frac{15}{20}=\frac{3}{4}\)
bài 3:
a) \(\frac{3}{2}\cdot\frac{4}{5}\cdot\frac{2}{3}=\left(\frac{3}{2}\cdot\frac{2}{3}\right)\cdot\frac{4}{5}=1\cdot\frac{4}{5}=\frac{4}{5}\)
b) \(\frac{6}{7}\cdot\frac{5}{3}\cdot\frac{7}{6}=\left(\frac{6}{7}\cdot\frac{7}{6}\right)\cdot\frac{5}{3}=1\cdot\frac{5}{3}=\frac{5}{3}\)
bài 4:
a) \(\frac{2}{5}\cdot\frac{1}{4}+\frac{3}{4}\cdot\frac{2}{5}=\frac{2}{5}\cdot\left(\frac{1}{4}+\frac{3}{4}\right)=\frac{2}{5}\cdot1=\frac{2}{5}\)
b) \(\frac{6}{11}:\frac{2}{3}+\frac{5}{11}:\frac{2}{3}=\left(\frac{6}{11}+\frac{5}{11}\right):\frac{2}{3}=1:\frac{2}{3}=\frac{3}{2}\)
Bài 1:
6/11 + 1/3 + 5/11
= ( 6/11 + 5/11) + 1/3
= 11/11 + 1/3
= 1 + 1/3
= 3/3 +1/3
= 4/3
Bài 2:
1/2 + 1/6 + 1/12 + 1/20
= ( 1/2 + 1/6 + 1/12 ) + 1/20
= ( 6/12 + 2/12 + 1/12 ) + 1/20
=9/12 + 1/20
= 3/4 +1/20
= 15/20 + 1/20
= 16/20 = 4/5
Bài 3:
a) \(\frac{3}{2}\times\frac{4}{5}\times\frac{2}{3}\) \(=\left(\frac{3}{2}\times\frac{2}{3}\right)\times\frac{4}{5}\)\(=1\times\frac{4}{5}=\frac{4}{5}\)
b) \(\frac{6}{7}\times\left(\frac{5}{3}\times\frac{7}{6}\right)\) \(=\frac{6}{7}\times\frac{35}{18}\)\(=\frac{1\times5}{7\times3}=\frac{5}{21}\)
Bài 4:
a) 2/5 x 1/4 + 3/4 x 2/5
= 2/5 x ( 1/4 + 3/4)
= 2/5 x 1
= 2/5
b) 6/11 : 2/3 +5/11 : 2/3
= ( 6/11 + 5/11) x 3/2
= 11/11 x 3/2
= 1 x 3/2
= 3/2
....
a, \(\frac{2}{3}+\frac{2}{3}+\frac{6}{3}=\frac{10}{3}\)
b,\(\frac{3}{4}+\frac{3}{4}+\frac{3}{2}=\frac{6}{4}+\frac{3}{2}=\frac{3}{2}+\frac{3}{2}=\frac{6}{2}=3\)
a) \(\frac{12}{25}+\frac{3}{5}+\frac{13}{25}\)
= \(\left(\frac{12}{25}+\frac{13}{25}\right)+\frac{3}{5}\)
= \(\frac{25}{25}+\frac{3}{5}\)
= \(1+\frac{3}{5}\)
= \(\frac{1}{1}+\frac{3}{5}\)
= \(\frac{5}{5}+\frac{3}{5}\)
= \(\frac{8}{5}\)
bài này tớ mà làm sai thì tớ ......................ko lm người........-_-
a) \(\frac{12}{25}+\frac{3}{5}+\frac{13}{25}\)
= \(\frac{12}{25}+\frac{15}{25}+\frac{13}{25}\)
= \(\frac{12+15+13}{25}\)
= \(\frac{40}{25}\)
= \(\frac{8}{5}\)
b) \(\frac{3}{2}+\frac{2}{3}+\frac{4}{3}\)
= \(\frac{9}{6}+\frac{4}{6}+\frac{8}{6}\)
= \(\frac{9+4+8}{6}\)
= \(\frac{21}{6}\)
= \(\frac{7}{2}\)
Ta có: 272727x28 - 282828x27 = 27x10101x28 - 28x10101x27 = 0
Vậy, phép tính đã cho bằng 0
4) \(\frac{29x101-101}{2x19x101+4x101}\)
= \(\frac{\left(29-1\right)x101}{\left(38-4\right)x101}\)
=\(\frac{28}{34}=\frac{14}{17}\)
5) \(\left(\frac{2}{7}+\frac{11}{7}+\frac{1}{7}\right)-\frac{3}{8}-\frac{5}{8}+\frac{1}{3}\)
= \(\frac{14}{7}-\frac{8}{8}+\frac{1}{3}\)
= \(2-1+\frac{1}{3}=\frac{4}{3}\)
Nhớ tk cho mình nhé
1\(\frac{423133x846267+423134}{423133x846267+423134}=1\))
\(\frac{\left(423133+1\right)x846267-423133}{423133x846267+423134}\)
=\(\frac{423133x846267+846267-423133}{423133x846267+423134}\)
= \(\frac{423133x846267+423134}{423133x846267+423134}\)
= 1
Nhớ tk cho mình nhé (các câu sau làm riêng cho đỡ dài
\(=\frac{3}{4}\left(\frac{8}{9}+\frac{2}{3}\right)=\frac{3}{4}\left(\frac{8}{9}+\frac{6}{9}\right)=\frac{3}{4}x\frac{14}{9}=\frac{7}{6}..\)
mình nhầm chỗ \(\frac{8}{9}\)và \(\frac{3}{4}\)có một dấu cộng
tính nhanh :
C= \(\frac{1}{3}\)+\(\frac{1}{10}\)+\(\frac{1}{15}\)+..................+\(\frac{1}{45}\)
C=\(\frac{1}{3}+\frac{1}{10}+\frac{1}{15}+\frac{1}{20}+\frac{1}{25}+\frac{1}{30}+\frac{1}{35}+\frac{1}{40}\)
=\(\frac{1}{3}+\frac{1}{15}+\frac{1}{10}+\frac{1}{20}+\frac{1}{30}+\frac{1}{40}+\frac{1}{25}+\frac{1}{35}\)
=\(\frac{5}{15}+\frac{1}{15}+\frac{4}{40}+\frac{2}{40}+\frac{1}{40}+\frac{1}{30}+\frac{1}{25}+\frac{1}{35}\)
=\(\frac{6}{15}+\frac{7}{40}+\frac{107}{1050}\)
\(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{12}{15}+\frac{22}{33}+\frac{48}{64}\)
\(=\frac{11}{33}+\frac{16}{64}+\frac{3}{15}+\frac{12}{15}+\frac{22}{33}+\frac{48}{64}\)
\(=\left(\frac{11}{33}+\frac{22}{33}\right)+\left(\frac{16}{64}+\frac{48}{64}\right)+\left(\frac{3}{15}+\frac{12}{15}\right)\)
\(\frac{33}{33}+\frac{64}{64}+\frac{15}{15}\)
\(=1+1+1\)
\(=3\)
Trả lời
3/1.4+3/4.7+3/7.10
=3/1.3/10
=3/10
Chúc bạn học tốt #
\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}\)
\(=\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}\)
\(=\frac{1}{1}-\frac{1}{10}=\frac{9}{10}\)