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\(1)\)\(-\dfrac{10}{11}.\dfrac{8}{9}+\dfrac{7}{18}.\dfrac{10}{11}\)
\(=\dfrac{10}{11}\left(-\dfrac{8}{9}+\dfrac{7}{18}\right)\)
\(=\dfrac{10}{11}\left(\dfrac{-16}{18}+\dfrac{7}{18}\right)\)
\(=\dfrac{10}{11}.\left(-\dfrac{1}{2}\right)=-\dfrac{5}{11}\)
\(2)\)\(\dfrac{12}{25}.\dfrac{23}{7}-\dfrac{12}{7}.\dfrac{13}{25}\)
\(=\dfrac{12}{7}.\dfrac{23}{25}-\dfrac{12}{7}.\dfrac{13}{25}\)
\(=\dfrac{12}{7}.\left(\dfrac{23}{25}-\dfrac{13}{25}\right)\)
\(=\dfrac{12}{7}.\dfrac{2}{5}=\dfrac{24}{35}\)
\(3)\)\(\dfrac{3}{7}.\dfrac{16}{15}-\dfrac{2}{15}.\dfrac{-3}{7}\)
\(=\dfrac{3}{7}.\dfrac{16}{15}-\dfrac{3}{7}.\dfrac{-2}{15}\)
\(=\dfrac{3}{7}.\left(\dfrac{16}{15}+\dfrac{2}{15}\right)\)
\(=\dfrac{3}{7}.\dfrac{18}{15}=\dfrac{18}{35}\)
\(4)\)\(-\dfrac{4}{13}.\dfrac{5}{17}+\dfrac{-12}{13}.\dfrac{4}{17}\)
\(=-\dfrac{4}{13}.\dfrac{5}{17}+\dfrac{-4}{13}.\dfrac{12}{17}\)
\(=-\dfrac{4}{13}.\left(\dfrac{5}{17}+\dfrac{12}{17}\right)\)
\(=-\dfrac{4}{13}.\dfrac{17}{17}=-\dfrac{4}{13}\)
`#040911`
`1)`
`-10/11 * 8/9 + 7/18 . 10/11`
`= 10/11 * (-8/9 + 7/18)`
`= 10/11 * (-1/2)`
`= -5/11`
`2)`
`12/25 * 23/7 - 12/7 *13/25`
`= 12/7 * 23/25 - 12/7 * 13/25`
`= 12/7 * (23/25 - 13/25)`
`= 12/7 * 2/5`
`= 24/35`
`3)`
`3/7 * 16/15 - 2/15 * (-3)/7`
`= 3/7 * (16/15 + 2/15)`
`= 3/7 * 6/5`
`= 18/35`
`4)`
`-4/13 * 5/17 + (-12)/13 * 4/17`
`= -4/17 * 5/13 + (-12)/13 * 4/17`
`= 4/17 * (-5/13 - 12/13)`
`= 4/17 * (-17)/13`
`= -4/13`
a) (-37) + 14 + 26 + 37
= [(-37) + 37] + (14 + 26)
= 0 + 40 = 40
b) (-24) + 6 + 10 + 24
= [(-24) + 24] + (10 + 6)
= 0 + 16 = 16
c) 15 + 23 + (-25) + (-23)
= [15 + (-25)] + [23 + (-23)]
= (-10) + 0 = -10
d) 60 + 33 + (-50) + (-33)
= [60 + (-50)] + [33 + (-33)]
= 10 + 0 = 10
e) (-16) + (-209) + (-14) + 209
= [(-16) + (-14)] + [(-209) + 209]
= (-30) + 0 = -30
f) \(-3^2+\left(-54\right)\div\left[\left(-2\right)^8+7\right]\times\left(-2\right)^2\\ =\left(-9\right)+\left(-54\right)\div263\times4\\ =\left(-9\right)+\dfrac{-216}{263}=\dfrac{-2583}{263}\)
a. \(\left[\left(-37\right)+37\right]+\left(14+16\right)\) = 30
B. \(\left[\left(-24\right)+24\right]+\left(10+6\right)\) = 16
C. \(\left[\left(-23\right)+23\right]+\left(15-23\right)\)= -8
d. \(\left[33-33\right]+\left(60-50\right)\) = 10
e. \(\left(209-209\right)+\left(-16-14\right)\)= -30
a) Ta có: 2002/2003 < 1 (1)
14/13 > 1 (2)
Từ (1) và (2) => 2002/2003 < 14/13
a) \(11^9+12^9+13^9+14^9+15^9+16^9\)
\(=11^{4.2}.11+12^{4.2}.12+13^{4.2}.13+14^{4.2}.14+15^9+16^9\)
\(=...1.11+...6.12+...1.13+...6.14+...5+...6\)
\(=...1+...2+...3+...4+...5+...6\)
\(=...1\)
Vậy biểu thức trên có chũ số tận cùng là 1
b) \(25^7+26^7+27^7+28^7+29^7+29^7+30^7+31^7\)
\(=...5+...6+27^4.27^3+28^4.28^3+29^4.29^3+29^4.29^3+...0+...1\)
\(=...5+...6+...3+...8+...9+...9+...0+...1\)
\(=...1\)
Vậy biểu thức trên có chữ số tận cùng là 1
e) -28-[-7-(11+23)-9]
=-28-(-7-11-23-9)
=-28+7+11+23+9=80
j) -[16-(-20)+(-30)-(-11-37)]
=-(16+20-30+11+37)=-16-20+30-11-37=-22