1) \(=\left(\frac{3}{5}+\frac{2}{5}\right).\frac{6}{11}\)

\(=1.\frac{6}{11}\)

\(=\frac{6}{11}\)

2)\(\frac{17}{25}.\left(\frac{11}{19}+\frac{6}{19}+\frac{2}{19}\right)\)

\(=\frac{17}{25}.1\)

\(=\frac{17}{25}\)

a )     \(\frac{5}{11}\times\frac{7}{25}\times\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5\times7\times15\times1}{11\times25\times11\times5}\)

\(=\frac{1\times7\times3\times1}{11\times5\times11\times1}\)

\(=\frac{21}{\left(10\times5+5\times1\right)\times11}\)

\(=\frac{21}{55\times11}\)

\(=\frac{21}{55\times10+55}\)

\(=\frac{21}{550+55}\)

\(=\frac{21}{605}\)   ( quá đơn giản ) 

\(\)

A) \(\frac{5}{11}\times\frac{7}{25}-\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5\times7}{11\times25}-\frac{15\times1}{11\times5}\)

\(=\frac{35}{10\times25+25}-\frac{15}{55}\)

\(=\frac{35}{250+25}-\frac{15}{55}\)

\(=\frac{35}{275}-\frac{15}{55}\)

\(=\frac{7}{55}-\frac{15}{55}\)

\(=\frac{7-15}{55}\)

\(=\frac{-8}{55}\)

a: \(\frac{5}{11}\times\frac{7}{25}+\frac{15}{11}\times\frac15\)

\(=\frac{7}{11\times5}+\frac{3}{11}=\frac{7+3\times5}{11\times5}=\frac{22}{55}=\frac25\)

b: \(\frac37\times\frac{25}{19}-\frac17\times\frac{18}{19}\)

\(=\frac{75}{7\times19}-\frac{18}{7\times19}=\frac{57}{7\times19}=\frac37\)

a ( 1+2+3+4+....+99)*(13*15-12*25-15)
= ( 1+2+3+4+....+99)*[15*(13-1)-12*25)]
=( 1+2+3+4+....+99)*[15*12-12*25]
=( 1+2+3+4+....+99)*[12*(15-25)]
=( 1+2+3+4+....+99)*[12*(-10)]
=( 1+2+3+4+....+99)*(-120)
= -594000
b 3*5*36+15+42+30*11
=15*36+15*1+42+15*22
=15*(36+1+22)+42
=15*59+42
=885+42
=927
Tick cho mk nha
 

a. ( 1+2+3+4+....+99)*(13*15-12*25-15)

=( 1+2+3+4+....+99) . 0

=0

 b 3*5*36+15+42+30*11

=540 + 15 +42 + 330

=927

a, \(\frac{5}{11}\times\frac{7}{25}+\frac{15}{11}\times\frac{1}{5}\)

\(=\frac{5}{11}\times\frac{7}{25}+\frac{5}{11}\times\frac{3}{5}\)

\(=\frac{5}{11}\times\left(\frac{7}{25}+\frac{3}{5}\right)\)

\(=\frac{5}{11}\times\frac{22}{25}\)

\(=\frac{2}{5}\)

b, \(\frac{3}{7}\times\frac{25}{19}-\frac{1}{7}\times\frac{18}{19}\)

\(=\frac{1}{7}\times\frac{75}{19}-\frac{1}{7}\times\frac{18}{19}\)

\(=\frac{1}{7}\times\left(\frac{75}{19}-\frac{18}{19}\right)\)

\(=\frac{1}{7}\times3\)

\(=\frac{3}{7}\)

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$#Shả$

`A)=5/17xx(15/34+19/34)`

`=5/17xx1=5/17`

`B)=(13/12+7/12)+1/3`

`=5/3+1/3=2`

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1a) \(\frac{12}{17}+\frac{19}{17}+\frac{8}{17}\)

\(=\left(\frac{12}{17}+\frac{8}{17}\right)+\frac{19}{17}\)

\(=\frac{20}{17}+\frac{19}{17}\)

\(=\frac{39}{17}\)

b) \(\frac{2}{5}+\frac{7}{12}+\frac{13}{12}\)

\(=\frac{2}{5}+\frac{5}{3}\)

\(=\frac{31}{15}\)

2) \(\frac{25}{3}-x=\frac{5}{6}\)

                \(x=\frac{25}{3}-\frac{5}{6}\)

                \(x=\frac{45}{6}\)

ủng hộ tớ nha

dấu ''/'' là chia à bạn?

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20

=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+20+10

=20+20+20+20+20+20+20+20+20+20+10

=20×10+10

=200+10

=210

= ( 1 + 19 ) + ( 2 + 18 ) + ( 3 + 17 ) + (4 + 16 ) + ( 5 + 15 ) + ( 6 + 14 ) + ( 7 + 13 ) + ( 8 + 12) + ( 9+ 11 ) + 20

= 20 + 20 + 20 +20 +  20 +20 + 20 + 20 + 20 +20

= 20 x 10

= 200

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