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5/-6+-5/12 +7/18 = -31/36
2/9+-3/10+-7/10 = 2/9+(-3/10+-7/10)=2/9+(-1)=7/9
-11/6 +2/5 +-1/6 =2/5 +(-11/6+-1/6)=2/5 + -2 =-8/5
-5/8+12/7+13/8+2/7 =(-5/8+13/8)+(12/7+2/7)=1+2=3
B= \(\dfrac{7}{6}+\dfrac{7}{12}+\dfrac{7}{20}+\dfrac{7}{30}+...+\dfrac{7}{1980}\)
B= \(\dfrac{7}{2\times3}+\dfrac{7}{3\times4}+\dfrac{7}{4\times5}+\dfrac{7}{5\times6}+...+\dfrac{7}{44\times45}\)
B= \(7\times\left(\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+...+\dfrac{1}{44\times45}\right)\)
B= 7\(\times\) \(\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{44}-\dfrac{1}{45}\right)\)
B= 7\(\times\) \(\left(\dfrac{1}{2}-\dfrac{1}{45}\right)\)
B= 7\(\times\) \(\dfrac{43}{90}\)
B= \(\dfrac{301}{90}\)
trong các phân số -3/4, 6/-7, -7/-8, -11/12, phân số nào nhỏ nhất là:
A:-3/4
B:6/-7
C:-7/-8
D:-11/12
a) 7/10+6/10\(=\frac{13}{10}\)
b) -5/9+2/9\(=\frac{-1}{3}\)
c)1/7+1 6/7\(=2\)
d) 3/13+10/3+1\(=\frac{71}{26}\)
e) 5/12-7/12\(=\frac{-1}{6}\)
f) 7/6+5/6-1/6\(=\frac{11}{6}\)
g) -3/20+7/20-9/20\(=\frac{-1}{4}\)
học tốt
a: \(=\dfrac{-5}{8}+\dfrac{7}{12}=\dfrac{-15}{24}+\dfrac{14}{24}=\dfrac{-1}{24}\)
b: \(=\dfrac{3}{4}-\dfrac{5}{6}+\dfrac{11}{12}=\dfrac{9}{12}-\dfrac{10}{12}+\dfrac{11}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)
c: \(=\dfrac{6}{36}-\dfrac{1}{36}=\dfrac{5}{36}\)
d: \(=\dfrac{5}{12}+\dfrac{5}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)
e: \(=\dfrac{-8}{56}-\dfrac{7}{56}=\dfrac{-15}{56}\)
f: \(=\dfrac{-5}{15}+\dfrac{3}{25}=\dfrac{-25}{75}+\dfrac{9}{75}=\dfrac{-16}{75}\)
\(12^7:6^7=\left(12:6\right)^7=2^7\)
đây nha
127:67
=(12:6)7
=27