1/2x5/6+1/2x11/6
rút gọn các phân số sau
a/ 2^3x3^4 / 2^2x3^2x5
2^4x5^2x11^2x7 / 2^3x5^3x7^2x11
b/ 121x75x130x169 / 39x60x11x198
c/1998x1990+3978 / 1992x1991-3984
a/\(\frac{2^3\cdot3^4}{2^2\cdot3^2\cdot5}=\frac{18}{5}\)\(\frac{2^4\cdot5^2\cdot11^2\cdot7}{2^3\cdot5^3\cdot7^2\cdot11}=\frac{2\cdot11}{5\cdot7}=\frac{22}{35}\)
b/\(\frac{121\cdot75\cdot130\cdot169}{39\cdot60\cdot11\cdot198}=\frac{11^2\cdot5^3\cdot13^3\cdot2\cdot3}{2^3\cdot3^4\cdot5\cdot11^2\cdot13}=\frac{5^2\cdot13^2}{2^2\cdot3^3}=\frac{4225}{108}\)
c/\(\frac{1998\cdot1990+3978}{1992\cdot1991-3984}=\frac{2^2\cdot3^3\cdot37\cdot5\cdot199+2\cdot3^2\cdot13\cdot17}{2^3\cdot3\cdot83\cdot11\cdot181-2^4\cdot3\cdot83}=\frac{2\cdot3^2\cdot11\cdot20101}{2^3\cdot3^3\cdot13\cdot17\cdot83}=\frac{11\cdot20101}{2^2\cdot3\cdot13\cdot17\cdot83}\)
2x|x+7/6| +|x|- 7/6 = |2x11/5|
1+2x5-8+29÷2+6-9+6-8+3-7+6+8+12-134+567=????
Tính nhanh:
a)1/3+2/3+5/12+4/3+1/12 b)3x5/6+5/6+2x5/6
c)___112x113+112x113_________
224x226+224x226
1/1x2+3/2x5+5/5x10+4/10x14+6/14x20
A = \(\dfrac{1}{1\times2}\) + \(\dfrac{3}{2\times5}\) + \(\dfrac{5}{5\times10}\) + \(\dfrac{4}{10\times14}\) + \(\dfrac{6}{14\times20}\)
A = \(\dfrac{1}{1}\) - \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) - \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\) - \(\dfrac{1}{10}\) + \(\dfrac{1}{10}\) - \(\dfrac{1}{14}\) + \(\dfrac{1}{14}\) - \(\dfrac{1}{20}\)
A = \(\dfrac{1}{1}\) - \(\dfrac{1}{20}\)
A = \(\dfrac{19}{20}\)
6 x5/3 7:8/4+1/3 2x5/8-1/2 3/7:5/6x1/4
10
\(\dfrac{23}{6}\)
\(\dfrac{3}{4}\)
\(\dfrac{9}{70}\)
6 x5/3=10 7:8/4+1/3=23/6 2x5/8-1/2=3/4 3/7:5/6x1/4=9/70
1+2x5+6x5-8-8x69-969+5x5+6+4+4+4-5x6
Trong các phép tính sau, những phép tính nào làm đúng? ( CHỌN NHIỀU ĐÁP ÁN )
A 3/4 + 1/3 = 3+1 /4 + 3 = 4/7
B 7/9 - 1/3 = 7- 1/ 9- 3 = 6/6 = 1
C 6/7 x 2/5 = 6x2 / 2x5 = 12/35
D 5/6 : 1/3 = 5/6 x 3/1 = 5/2
chứng minh rằng\(\frac{a}{b}=\frac{c}{d}thì\frac{a}{b}=\frac{a+c}{b+d}\)
rút gọn phân số:a)\(\frac{2^3x3^4}{2^2x3^2x5}\) b)\(\frac{2^4x5^2x11^2x7}{2^3x5^3x7^2x11}\) c)\(\frac{121x75x130x169}{39x60x11x198}\) d)\(\frac{1998x1990+3978}{1992x1991-3984}\)