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

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

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)  \(\frac{84}{4}+\frac{3^9}{3^7}+5^0=21+3^2+1=31\)

a) \(\dfrac{\dfrac{3}{14}-\dfrac{3}{17}+\dfrac{3}{19}}{\dfrac{5}{19}+\dfrac{5}{14}-\dfrac{5}{17}}=\dfrac{3\left(\dfrac{1}{14}-\dfrac{1}{17}+\dfrac{1}{19}\right)}{5\left(\dfrac{1}{14}-\dfrac{1}{17}+\dfrac{1}{19}\right)}=\dfrac{3}{5}\)

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) 

wow! mù mắt. Ido tính toán có khác!

C2:(32+1)x32:2=528

bạn tính thử xem đúng đấy.

wowwowwow

\(a)34/323; 57/323 b)204/255; 165/255 c)4034070/4036080; 4034072/4036080 d)875/980; 560/980 e)85/340; 68/340\)

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

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

đây nha 

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

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

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

a) <     b) >     c) <