Tinh nhanh :
a . 1/4 + 2/5 + 6/8 + 9/15 + 8/1
b . 15/31 * 16/43 + 15/31 * 27 4
tinh nhanh
a 1/4 + 2/5 + 6/8 + 9/15 + 8/1 b . 15/31 * 16/43 + 15/31 * 27/43
a) \(\frac{1}{4}+\frac{2}{5}+\frac{6}{8}+\frac{9}{15}+\frac{8}{1}\)
\(=\left(\frac{1}{4}+\frac{6}{8}\right)+\left(\frac{2}{5}+\frac{9}{15}\right)+\frac{8}{1}\)
\(=\left(\frac{1}{4}+\frac{3}{4}\right)+\left(\frac{2}{5}+\frac{3}{5}\right)+\frac{8}{1}\)
\(=\frac{4}{4}+\frac{5}{5}+\frac{8}{1}\)
\(=1+1+8\)
\(=10\)
b) \(\frac{15}{31}\cdot\frac{16}{43}+\frac{15}{31}\cdot\frac{27}{43}\)
\(=\frac{15}{31}\cdot\left(\frac{16}{43}+\frac{27}{43}\right)\)
\(=\frac{15}{31}\cdot\frac{43}{43}\)
\(=\frac{15}{31}\cdot1=\frac{15}{31}\)
**** !
1.Tìm các số nguyên x:
5/17+-4/9+-20/31+12/17+-11/31<x<=-3/7+7/15+4/-7+8/15+2/3
2. Tính
A=5-10/19+15/143-5/81+8-16/26+24/243-8/181
6-12/19+18/143-6/81+9-18/26+27/243-9/181
Tính :
2/5 + 11/15 =
7/8 - 7/9 =
11/13 x 26/31 =
16/24 : 4 =
30 : 6/5 =
9/16 : 4 =
1/2 : 1/3 x 8/15 =
\(\dfrac{2}{5}+\dfrac{11}{15}=\dfrac{6}{15}+\dfrac{11}{15}=\dfrac{17}{15}\)
\(\dfrac{7}{8}-\dfrac{7}{9}=\dfrac{63}{72}-\dfrac{56}{72}=\dfrac{7}{72}\)
\(\dfrac{11}{13}\times\dfrac{26}{31}=\dfrac{22}{31}\)
\(\dfrac{16}{24}:4=\dfrac{16}{24}\times\dfrac{1}{4}=\dfrac{4}{24}=\dfrac{1}{6}\)
\(30:\dfrac{6}{5}=30\times\dfrac{5}{6}=25\)
\(\dfrac{9}{16}:4=\dfrac{9}{16}\times\dfrac{1}{4}=\dfrac{9}{64}\)
\(\dfrac{1}{2}:\dfrac{1}{3}\times\dfrac{8}{15}=\dfrac{1}{2}\times3\times\dfrac{8}{15}=\dfrac{4}{5}\)
2/5 + 11/15 = 17/15
7/8 - 7/9 = 7/72
11/13 x 26/31 = 22/31
16/24 : 4 = 1/6
30 : 6/5 = 25
9/16 : 4 = 9/64
1/2 : 1/3 x 8/15 = 3/2 x 8/15 = 4/5
4.Tinh
a,\(\frac{4^{30}.3^{43}}{2^{53}.27^{15}}\)
b,\(\frac{\left(-27\right)^{10}.16^{25}}{6^{30}.\left(-32\right)^{15}}\)
c,\(\left(\frac{-2}{17}\right)^3.\left(\frac{-17}{35}\right)^3.\left(\frac{35}{3}\right)^3\)
d,\(\frac{3^{31}.25^8-9^{14}.5^{15}}{27^{10}.5^{15}-3^{30}.5^{17}}\)
e,\(2^{^2}+4^{^2}+6^2+..........+24^2\left(1^2+2^2+3^2+....+12^2=650\right)\)
1/8 + 2/5 - 4/32
-1/15 + 23/27 + -14/15 + 31/27
3/7 . 22/21 + 3/7 . 5/21 + 15/21 . 3/7
-8/9 : 2/3 +1/9 : -2/3
a: =1/8-1/8+2/5=2/5
b: =(-1/15-14/15)+(23/27+31/27)=2-1=1
c: \(=\dfrac{3}{7}\left(\dfrac{22}{21}+\dfrac{5}{21}+\dfrac{15}{21}\right)=\dfrac{3}{7}\cdot2=\dfrac{6}{7}\)
d: \(=\dfrac{-8}{9}\cdot\dfrac{3}{2}+\dfrac{1}{9}\cdot\dfrac{-3}{2}=-\dfrac{3}{2}\)
tính 1*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16*17*18*19*0*20*21*22*23*24*25*26*27*28*29*30*31*32
ai nhanh mình tích cho
1*2*3*4*5*6*7*8*9*10*11*12*13*14*15*16*17*18*19*0*20*21*22*23*24*25*26*27*28*29*30*31*32=0
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=?
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50.
Có ai rảnh đâu mà đi ngồi cộng ngần đấy số ra.
a 12 – 34 b 23 – 47 c 31 – 23 d 9 – 5 e 4 – 15 25 f 23 13 17 57 g 4 . 9 6 . 12 – 7 h 14 6 19 14 19 i 56 – 8. 27 7 j 8 5 . 2 – 3 6 k 4 . 3 125 . 25 8 l 9 6 . 3 – 4 7 m 45. 18 – 15 – 18. 45 – 15
Tách từng câu ra giùm, như này ai giải nổi:)))))