TÍNH NHANH :
A . 2/3 . 15/17 + 2/3 . 2/17
B . 20/19 : 3/7 - 1/19 : 3/7
CHÚ Ý : DẤU CHẤM LÀ NHÂN
K
Khách
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Những câu hỏi liên quan
11 tháng 8 2018
a, \(\frac{2}{3}\).\(\frac{15}{17}\)+\(\frac{2}{3}\).\(\frac{2}{17}\)
= \(\frac{2}{3}\).( \(\frac{15}{17}\)+ \(\frac{2}{17}\))
= \(\frac{2}{3}\). 1
=\(\frac{2}{3}\)
b,\(\frac{20}{19}\):\(\frac{3}{7}\)- \(\frac{1}{19}\): \(\frac{3}{7}\)
= ,\(\frac{20}{19}\).\(\frac{7}{3}\)- \(\frac{1}{19}\).\(\frac{7}{3}\)
= \(\frac{7}{3}\).(\(\frac{20}{19}\)-\(\frac{1}{19}\))
=\(\frac{7}{3}\).1
=\(\frac{7}{3}\)
HT
14 tháng 8 2017
a) \(12.79-64.37+12.21-36.37+12000\)
\(=\left(12.79+12.21\right)-\left(64.37+36.37\right)+12000\)
\(=\left[12\left(79+21\right)-37\left(64+36\right)+12000\right]\)
\(=12.100-37.100+12000\)
\(=1200-3700+12000\)
\(=9500\)
b) \(112.39+1237+112.61\)
\(=\left(112.39+112.61\right)+1237\)
\(=112\left(39+61\right)+1237\)
\(=112.100+1237\)
\(=11200+1237\)
\(=12437\)
c) \(35.762+351-35.662\)
\(=35\left(762-662\right)+351\)
\(=35.100+351\)
\(=3500+351\)
\(=3851\)
d) \(\frac{20}{4}-\frac{5^9}{5^8}=5-5=0\)
e) \(\left(\frac{5^{19}}{5^{17}}-4\right):7=\left(5^2-4\right):7=21:7=3\)
f) \(\frac{84}{4}+\frac{3^9}{3^7}+5^0=21+3^2+1=31\)
DT
Đỗ Thanh Hải
CTVVIP
11 tháng 3 2021
a) \(\dfrac{\dfrac{3}{14}-\dfrac{3}{17}+\dfrac{3}{19}}{\dfrac{5}{19}+\dfrac{5}{14}-\dfrac{5}{17}}=\dfrac{3\left(\dfrac{1}{14}-\dfrac{1}{17}+\dfrac{1}{19}\right)}{5\left(\dfrac{1}{14}-\dfrac{1}{17}+\dfrac{1}{19}\right)}=\dfrac{3}{5}\)
DT
Đỗ Thanh Hải
CTVVIP
11 tháng 3 2021
c) \(\dfrac{\dfrac{2}{7}+\dfrac{2}{5}+\dfrac{2}{17}-\dfrac{2}{193}}{\dfrac{3}{7}+\dfrac{3}{5}+\dfrac{3}{17}-\dfrac{3}{293}}=\dfrac{2\left(\dfrac{1}{7}+\dfrac{1}{5}+\dfrac{1}{17}-\dfrac{1}{193}\right)}{3\left(\dfrac{1}{7}+\dfrac{1}{5}+\dfrac{1}{17}-\dfrac{1}{193}\right)}=\dfrac{2}{3}\)
d)
21 tháng 2 2022
\(a)34/323; 57/323 b)204/255; 165/255 c)4034070/4036080; 4034072/4036080 d)875/980; 560/980 e)85/340; 68/340\)
21 tháng 2 2022
a: 2/19=34/323
3/17=57/323
b: 12/15=204/255
11/17=165/255
c: 2007/2008=4034070/4036080
2009/2010=4034072/4036080
d: 25/28=125/140
20/35=80/140
e: 17/60=1/4=5/20
1/5=4/20
14 tháng 4 2023
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
9 tháng 8 2015
a) = 17/19 - 17/19 + 27/35 + 35/35 = 0 + 62/35
b) = 1/3 x 4/5 + 1/3 x6/5 + 1/3 x 2 = 1/3(4/5 + 6/5 + 2) = 1/3 x 4 = = 4/3
c) 4/7 x 2/9 + 4/7 x 7/9 + 2/3 = 4/7 x (2/9 + 7/9) + 2/3 = 4/7 x 1 + 2/3 = 26/21
4 tháng 3 2022
A) 17/19 - 17/19 + 27/35 + 35/35 = 0 + 62/35
B) 1/3 x 4/5 + 1/3 x 6/5 + 1/3 x 2 = 1/3 x(4/5 + 6/5 x 2 ) = 1/3 x 4 = 4/3
c) TƯƠNG TỰ CÂU A VÀ B
* HOKTOT*
NHA
Mn đã trả lời rùi mà~
A. \(\frac{2}{3}.\frac{15}{17}+\frac{2}{3}.\frac{2}{17}\)
=\(\frac{2}{3}.\left(\frac{15}{17}+\frac{2}{17}\right)\)
=\(\frac{2}{3}.1\)
=\(\frac{2}{3}\)
B. \(\frac{20}{19}:\frac{3}{7}-\frac{1}{19}:\frac{3}{7}\)
=\(\left(\frac{20}{19}-\frac{1}{19}\right):\frac{3}{7}\)
=1:\(\frac{3}{7}\)
=\(\frac{7}{3}\)