Tính : a , 15 . 2323 + 4 . 2323 - 5 . 7b, 49 . 213 + 87...
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Tính :
a , 15 . 2323 + 4 . 2323 - 5 . 7
b, 49 . 213 + 87 . 7272
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Những câu hỏi liên quan
PJ
1
23 tháng 7 2018
2323/202+2323/606+2323/1212+2323/2020+2323/3030+2323/4242+2323/5656+2323/7272+2323/9090.=
\(\frac{23\times101}{2\times101}+\frac{23\times101}{6\times101}+\frac{23\times101}{12\times101}+....+\frac{23\times101}{72\times101}+\frac{23\times101}{90\times101} \)
=\(\frac{23}{2}+\frac{23}{6}+..........+\frac{23}{72}+\frac{23}{90}\)
=\(23\times\left(\frac{1}{1\times2}+\frac{1}{2\times3}+.....+\frac{1}{9\times10}\right)\)
=\(23\times\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{9}-\frac{1}{10}_{ }\right)\)
=\(23\left(1-\frac{1}{10}\right)_{ }\)
=\(23\times\frac{9}{10}\)
==\(\frac{207}{10}\)
chúc học giỏi nha bn
NP
4
7 tháng 5 2017
1919/2323x464646/747474x37/19
=19/23x46/74x37/19
=\(\frac{19.46.37}{23.74.19}=\frac{1.2.1}{1.2.1}=1\)
LV
2
7 tháng 5 2017
35 x 12 - 15 x 28 + \(\frac{23}{49}\)- \(\frac{23}{49}\)+ 2017
= 35 x 12 - 15 x 28 + 0 + 2017
= 35 x 12 - 15 x 28 + 2017
= 420 - 420 + 2017
= 0 + 2017
= 2017
PH
1
30 tháng 8 2016
a, 4/20+16/42+6/15+-3/5+2/2+-10/21=1/5+8/21+2/5+-3/5+2/2+-16/21=(1/5+2/5+-3/5)+(8/21=-16/21)+1=-2/21+1=-19/21 b,42/46+250/186+-2121/2323+-125125/143143 =21/23+125/93+-21/23+-125/143 =(21/23+-21/23)+(-125/143+125/93) =6250/13299
VP
3
12 tháng 7 2017
35 x 12 - 15 x 28 + \(\frac{2323}{4949}-\frac{23}{49}\)+ 2010
= (420 - 420 )+ \(\left(\frac{23}{49}-\frac{23}{49}\right)\)+ 2010
= 0 + 0 + 2010 = 2010 .
12 tháng 7 2017
35 x 12 -15 x28+2323/4949-23/49+2010
=35x12-15x28+23/49-23/49+2010
=420-420+0+2010
=0+0+2010
=2010
20 tháng 1 2024
a: \(C=\dfrac{-1}{2}:\dfrac{-2}{3}:\dfrac{-3}{4}\)
\(=\dfrac{-1}{2}\cdot\dfrac{3}{-2}\cdot\dfrac{4}{-3}\)
\(=-\dfrac{4}{4}=-1\)
b: \(D=\dfrac{-6}{5}:\dfrac{-5}{4}:\dfrac{-4}{3}\)
\(=-\dfrac{6}{5}\cdot\dfrac{4}{5}\cdot\dfrac{3}{4}\)
\(=\dfrac{-18}{25}\)
c: \(\dfrac{4}{20}+\dfrac{16}{42}+\dfrac{6}{15}+\dfrac{-3}{5}+\dfrac{2}{21}+\dfrac{-10}{21}+\dfrac{3}{20}\)
\(=\left(\dfrac{4}{20}+\dfrac{-3}{5}+\dfrac{6}{15}\right)+\left(\dfrac{16}{42}+\dfrac{2}{21}-\dfrac{10}{21}\right)+\dfrac{3}{20}\)
\(=\left(\dfrac{1}{5}-\dfrac{3}{5}+\dfrac{2}{5}\right)+\left(\dfrac{8}{21}+\dfrac{2}{21}-\dfrac{10}{21}\right)+\dfrac{3}{20}\)
\(=\dfrac{3}{20}\)
d: \(\dfrac{42}{46}+\dfrac{250}{186}+\dfrac{-2121}{2323}+\dfrac{-125125}{143143}\)
\(=\dfrac{21}{23}+\dfrac{125}{93}+\dfrac{-21}{21}+\dfrac{-125}{143}\)
\(=\dfrac{125}{93}-\dfrac{125}{143}=\dfrac{6250}{13299}\)
E
27 tháng 3 2021
a, \(\frac{4}{20}+\frac{16}{42}+\frac{6}{15}+\frac{-3}{5}+\frac{-10}{21}+\frac{3}{20}\)
\(=\left(\frac{4}{20}+\frac{-3}{5}+\frac{6}{15}+\frac{3}{20}\right)\)\(+\left(\frac{16}{42}+\frac{2}{21}+\frac{-10}{21}\right)\)
\(=\left(\frac{4}{20}+\frac{-12}{20}+\frac{8}{20}+\frac{3}{20}\right)\)\(+\left(\frac{8}{21}+\frac{2}{21}+\frac{-10}{21}\right)\)
\(=\frac{3}{20}\)
b,\(\frac{42}{46}+\frac{250}{186}+\frac{-2121}{2323}+\frac{-125125}{143143}\)
\(=\frac{21}{23}+\frac{125}{93}+\frac{-21}{23}+\frac{-125}{143}\)
\(=\left(\frac{21}{23}+\frac{-21}{23}\right)+\left(\frac{125}{93}+\frac{-125}{143}\right)\)
\(=\frac{6250}{13299}\)
N
0
DT
1
9 tháng 4 2017
Câu này dễ mà
\(=35.12-15.28+\frac{23}{49}-\frac{23}{49}+2010\)
\(=\left(420-420\right)+\left(\frac{23}{49}-\frac{23}{49}\right)+2010\)
\(=0+0+2010\)
\(=2010\)
NC
2
23 tháng 10 2015
a/
=2323 x (3434+5656)
=2323 x 9090
=21 116 070
b/
=1234 x (4244+4543)
=1234 x 8787
=10 843 159
a, 15 . 23 + 4 . 23 - 5 . 7
= 23(15 + 4) - 35
= 23 . 19 - 35
= 437 - 35
= 402
b, 49 . 213 + 87 . 72
= 10 437 + 1 044
= 9393
a)15.23+4.23-5.7
=345+92-35
=402
b) 49.213+87.72
=10437+6264
=16701
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