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a) (2 × 3 × 8)/(4 × 5 × 6 × 7)
= (6 × 2 × 4)/(4 × 5 × 6 × 7)
= 2/(5 × 7)
= 2/35
b) (36 × 22 × 51)/(11 × 17 × 72)
= (36 × 2 × 11 × 3 × 17)/(11 × 17 × 2 × 36)
= 3
Lời giải:
a.
\(\frac{2\times 3\times 8}{4\times 5\times 6\times 7}=\frac{2\times 24}{24\times 5\times 7}=\frac{2}{5\times 7}=\frac{2}{35}\)
b.
\(\frac{36\times 22\times 51}{11\times 17\times 72}=\frac{36\times 2\times 11\times 17\times 3}{11\times 17\times 72}=\frac{72\times 11\times 17\times 3}{11\times 17\times 72}=3\)
a) \(\frac{4\times5\times6\times7}{5\times6\times7\times8}\)
\(=\frac{4\times5\times6\times7}{5\times6\times7\times4\times2}\)
\(=\frac{1}{2}\)
b) \(\frac{10\times6\times7}{5\times14\times8}\)
\(=\frac{5\times2\times6\times7}{5\times7\times2\times8}\)
\(=\frac{3}{4}\)
tự gạch các từ giống nhau nha
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. 4/9 + 3/7 = 55/63 ; 3/4 + 7/24 =25/24 ; 1/3 + 2/9 + 4/27 =5/9 + 4/27 =19/27; 4 : 9/5 : 10/3 =20/9 : 10/3 =2/3
b. 5/6 - 3/8 =11/24; 7/15 - 11/30 =1/10 ; 8 x 3/5 : 12/5 =24/5 : 12/5 = 2 ; 2/3 + 1/6 - 7/12 =5/6 - 7/12 = 1/4
c.2 x 3 x 8 / 4 x 5 x 6 x 7= 2/35 ; 36 x 22 x 51 / 11 x 17 x 72 = 3
1.
a) \(\frac{16}{24}-\frac{1}{3}=\frac{16}{24}-\frac{8}{24}=\)\(\frac{8}{24}=\frac{1}{3}\)
b) \(\frac{4}{5}-\frac{12}{60}=\frac{48}{60}-\frac{12}{60}=\frac{36}{60}=\frac{9}{15}\)
3.
a)\(\frac{17}{6}-\frac{2}{6}=\frac{17-2}{6}=\frac{15}{6}\)
b) \(\frac{16}{15}-\frac{11}{15}=\frac{16-11}{15}=\frac{5}{15}=\frac{1}{3}\)
c) \(\frac{19}{12}-\frac{13}{12}=\frac{19-13}{12}=\frac{6}{12}=\frac{1}{2}\)
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) \(3\frac{4}{7}\times2\frac{4}{5}\)
\(=\frac{25}{7}\times\frac{14}{5}=\frac{350}{35}=10\)
b) \(\frac{4}{5}:\frac{1}{2}+\frac{17}{3}\)
\(=\frac{8}{5}+\frac{17}{3}\)
\(=\frac{109}{15}\)
c) \(5\frac{1}{3}-2\frac{1}{6}\)
\(=\frac{16}{3}-\frac{13}{6}\)
\(=\frac{32}{6}-\frac{13}{6}=\frac{19}{6}\)
d) \(4\frac{1}{2}:2\frac{1}{4}\)
\(=\frac{9}{2}:\frac{9}{4}=\frac{45}{18}\)
a , 2 / 35 chỉ cần rút gọn thôi
b , 3 cũng giống ý a
2x3x4x2/4x5x2x3x7
=2/5x7
=2/35
b)
36x11x2x17x3/11x17x36x2
=3