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a
\(\frac{3}{4}+\frac{1}{5}\)
\(=\frac{15}{20}+\frac{4}{20}\)
\(=\frac{19}{20}\)
b
\(\frac{1}{36}+\frac{5}{12}\)
\(\frac{5}{12}=\frac{5\times3}{12\times3}=\frac{15}{36}\)
\(\frac{1}{36}+\frac{15}{36}=\frac{16}{36}=\frac{4}{9}\)
c
\(\frac{3}{4}+\frac{1}{6}\)
\(=\frac{18}{24}+\frac{4}{24}\)
\(=\frac{22}{24}=\frac{12}{11}\)
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1.3/2>5/5>3/4>2/3>3/5>2/5
2.135/120 = 9/8 = 18/16= 36/32
72/84 = 36/42 = 6/7 = 12/14
3. ( Rất tiếc mình làm không được!!! SORRY)
4.
4242x12x15/2121x15x20
= 2x12/20
= 24/20
= 6/5
HT
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1.
\(\frac{5}{3}-\frac{1}{4}+\frac{1}{3}-\frac{3}{4}\)
\(=\left(\frac{5}{3}+\frac{1}{3}\right)-\left(\frac{1}{4}+\frac{3}{4}\right)\)
\(=2-1=1\)
\(\frac{2}{7}\cdot\frac{1}{5}+\frac{2}{7}\cdot\frac{4}{5}=\frac{2}{7}\cdot\left(\frac{1}{5}+\frac{4}{5}\right)=\frac{2}{7}\cdot1=\frac{2}{7}\)
#Louis
\(1.a)\frac{5}{3}-\frac{1}{4}+\frac{1}{3}-\frac{3}{4}\)
\(=\left(\frac{5}{3}+\frac{1}{3}\right)-\left(\frac{1}{4}+\frac{3}{4}\right)\)
\(=2-1\)
\(=1\)
\(b)\frac{2}{7}\times\frac{1}{5}+\frac{2}{7}\times\frac{4}{5}\)
\(=\frac{2}{7}\times\left(\frac{1}{5}+\frac{4}{5}\right)\)
\(=\frac{2}{7}\times1\)
\(=\frac{2}{7}\)
\(2.a)\frac{5}{6}+\frac{7}{12}-\frac{2}{9}\)
\(=\frac{30}{36}+\frac{21}{36}-\frac{8}{36}\)
\(=\frac{43}{36}\)
\(b)\frac{4}{9}\times\frac{5}{8}+\frac{1}{6}\)
\(=\frac{5}{18}+\frac{1}{6}=\frac{5}{18}+\frac{3}{18}\)
\(=\frac{8}{18}=\frac{4}{9}\)
\(c)2:\frac{3}{11}-\frac{13}{12}\)
\(=2\times\frac{11}{3}-\frac{13}{12}\)
\(=\frac{22}{3}-\frac{13}{12}\)
\(=\frac{25}{4}\)
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Trả lời :
A.12345+6789 = 19134
B.9876+54321 = 64097
C. 234+567 = 801
~ HT ~
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a,b,c là số tự nhiên thì làm ntn nhé:
Theo đề bài ta có:
b=c-15 (1)
a=c-6 (2)
a+b+c=69 (3)
thay (1) và (2) vào (3), ta có:
(c - 6) + (c - 15) + c = 69
c - 6 + c - 15 + c = 69
3.c -21 = 69
3.c = 90
c = 30
=> b=30-15=15
=> a=30-6=24
Chúc b học tốt nha!!!
Tính:
\(\dfrac{2}{3}+\dfrac{3}{4}+\dfrac{1}{6}\left(MSC:12\right)\\ \dfrac{2}{3}=\dfrac{2\times4}{3\times4}=\dfrac{8}{12};\\ \dfrac{3}{4}=\dfrac{3\times3}{4\times3}=\dfrac{9}{12};\\ \dfrac{1}{6}=\dfrac{1\times2}{6\times2}=\dfrac{2}{12}\\ =>\dfrac{8}{12}+\dfrac{9}{12}+\dfrac{2}{12}\\ =\dfrac{8+9+2}{12}\\ =\dfrac{19}{12}.\)
nhanh ạ