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1. a) \(\frac{6}{11}+\frac{7}{5}=\frac{30}{55}+\frac{77}{55}=\frac{30+77}{55}=\frac{107}{55}\)
b) \(\frac{9}{5}-\frac{6}{7}=\frac{63}{35}-\frac{30}{35}=\frac{63-30}{35}=\frac{33}{35}\)
c) \(\frac{11}{2}-3=\frac{11}{2}-\frac{3}{1}=\frac{11}{2}-\frac{6}{2}=\frac{11-6}{2}=\frac{5}{2}\)
d) \(15+\frac{1}{3}=\frac{15}{1}+\frac{1}{3}=\frac{45}{3}+\frac{1}{3}=\frac{45+1}{3}=\frac{46}{3}\)
2. a)\(\frac{3}{7}\cdot\frac{7}{2}=\frac{21}{14}\)
b) \(6\cdot\frac{7}{9}=\frac{42}{9}\)
c) \(\frac{8}{15}\cdot5=\frac{40}{15}\)
d) \(\frac{6}{13}\cdot\frac{26}{2}=\frac{156}{26}\)
Dấu chấm mấy bài trên thay thế cho dấu nhân nhá..
Cách 1:\(\left[\frac{7}{9}+\frac{11}{3}\right]-\frac{5}{3}\)\(=\frac{40}{9}\)\(-\frac{5}{3}\)\(=\frac{25}{9}\)
Cách 2 :\(\frac{7}{9}+\left[\frac{11}{3}-\frac{5}{3}\right]\)\(=\frac{7}{9}+\frac{2}{1}=\frac{25}{9}\)
Cách 1: \(\left[\frac{1}{3}+\frac{9}{7}\right]-\frac{8}{7}=\frac{34}{21}-\frac{8}{7}=\frac{10}{21}\)
Cách 2: \(\frac{1}{3}+\left[\frac{9}{7}-\frac{8}{7}\right]=\frac{1}{3}+\frac{1}{7}=\frac{7+3}{21}=\frac{10}{21}\)
a) ( 7/11 + 5/9 ) x 2
C1 : ( 7/11 + 5/9 ) x 2
= 118/99 x 2
= 236/99
C2 : ( 7/11 + 5/9 ) x 2
= 7/11 x 2 + 5/9 x 2
= 14/11 + 10/9
= 236/99
b) ( 2/3 + 7/9 ) : 2
C1 : ( 2/3 + 7/9 ) : 2
= 13/9 : 2
= 13/18
C2 : ( 2/3 + 7/9 ) : 2
= 2/3 : 2 + 7/9 : 2
= 1/3 + 7/18
= 13/18
a) \(\left(\frac{7}{11}+\frac{5}{9}\right)\times2\)
Cách 1: \(\left(\frac{7}{11}+\frac{5}{9}\right)\times2=\frac{118}{99}\times2=\frac{236}{99}\)
Cách 2: \(\left(\frac{7}{11}+\frac{5}{9}\right)\times2=\frac{7}{11}\times2+\frac{5}{9}\times2=\frac{14}{11}+\frac{10}{9}=\frac{236}{99}\)
b) \(\left(\frac{2}{3}+\frac{7}{9}\right):2\)
Cách 1: \(\left(\frac{2}{3}+\frac{7}{9}\right):2=\frac{13}{9}:2=\frac{13}{18}\)
Cách 2: \(\left(\frac{2}{3}+\frac{7}{9}\right):2=\frac{2}{3}:2+\frac{7}{9}:2=\frac{1}{3}+\frac{7}{18}=\frac{13}{18}\)
a] 4/12 ; 5/12 ; 11/2 ; 1/4
b] 1 ; 9/12; 12/5 ; 11/3
c] 8/21; 6/11;8/7
d] 2/3 ;2/7 15/2
a]1/3 5/12 11/2 1/4
b]1 3/4 12/5 33/9
c]8/21 6/11 8/7
d]2/3 2/7 15/2
Bài làm
a) \(\left(\frac{1}{2}+\frac{4}{7}\right)-\left(\frac{3}{7}-\frac{3}{10}\right)\)
\(=\frac{1}{2}+\frac{4}{7}-\frac{3}{7}+\frac{3}{10}\)
\(=\frac{35}{70}+\frac{40}{70}-\frac{30}{70}+\frac{21}{70}\)
\(=\frac{66}{70}\)
\(=\frac{33}{35}\)
b) \(\left(\frac{3}{5}x\frac{4}{5}x\frac{5}{9}\right):\left(\frac{7}{9}-\frac{3}{5}\right)\)
\(=\left(\frac{1}{5}x\frac{4}{3}\right):\left(\frac{35}{45}-\frac{27}{45}\right)\)
\(=\frac{4}{15}:\frac{8}{45}\)
\(=\frac{4}{15}.\frac{45}{8}\)
\(=\frac{1}{1}.\frac{3}{2}\)
\(=\frac{3}{2}\)
1, =4/9 x (3/7 + 2 x 4/7) - 1/9 - 3/9
= 4/9 x 1 - 1/9 - 3/9 = 0
2, = ( 22/5 x 5/22 ) x 12
= 1 x 12 = 12
Bài 1: Tính
\(a.\frac{15}{16}-\frac{7}{16}=\frac{15-7}{16}=\frac{8}{16}=\frac{1}{2}\)
\(b.\frac{7}{4}-\frac{3}{4}=\frac{7-3}{4}=\frac{4}{4}=1\)
\(c.\frac{9}{5}-\frac{3}{5}=\frac{9-3}{5}=\frac{6}{5}\)
\(d.\frac{17}{49}-\frac{12}{49}=\frac{17-12}{49}=\frac{5}{49}\)
Bài 2:Rút gọn rồi tính
\(a.\frac{2}{3}-\frac{3}{9}=\frac{2}{3}-\frac{1}{3}=\frac{2-1}{3}=\frac{1}{3}\)
\(b.\frac{7}{5}-\frac{15}{25}=\frac{7}{5}-\frac{3}{5}=\frac{7-3}{5}=\frac{4}{5}\)
Học tốt. K cho mik nha
