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20 tháng 11 2021

\(\frac{-1}{4}\)\(^2\).\(\frac{4}{11}\)+\(\frac{7}{11}\).\(\frac{-1}{4}\)\(^2\)

=(\(\frac{-1}{4}\))\(^2\)(\(\frac{4}{11}\)+\(\frac{7}{11}\))

=\(\frac{1}{16}\).\(\frac{11}{11}\)

=\(\frac{1}{16}\).1

=\(\frac{1}{16}\)

13 tháng 3 2020

a,\(0,5-\frac{5}{41}+\frac{1}{2}-\frac{36}{41}\)

=\(\frac{1}{2}-\frac{5}{41}+\frac{1}{2}-\frac{36}{41}\)

=\(\left(\frac{1}{2}+\frac{1}{2}\right)-\left(\frac{5}{41}+\frac{36}{41}\right)\)

\(1-1=0\)

b,\(\left(\frac{-1}{3}\right)^2.\frac{4}{11}+\frac{7}{11}.\left(\frac{1}{3}\right)^2\)

=\(\frac{1}{9}.\frac{4}{11}+\frac{7}{11}.\frac{1}{9}\)

=\(\frac{1}{9}\left(\frac{4}{11}+\frac{7}{11}\right)\)

=\(\frac{1}{9}.1=\frac{1}{9}\)

c,\(\left(\frac{-2}{3}+\frac{3}{7}\right):\frac{4}{5}+\left(\frac{-1}{3}+\frac{4}{7}\right):\frac{4}{5}\)

=\(\left(\frac{-2}{3}+\frac{3}{7}-\frac{1}{3}+\frac{4}{7}\right):\frac{4}{5}\)

=\(\left(-1+1\right).\frac{5}{4}=0.\frac{5}{4}\)=0

14 tháng 3 2020

cảm ơn

31 tháng 7 2023

A = 13/21.2/11 + 13/21.9/11 + 8/21
= (13/21) + (13/21) + (8/21)
= (13 + 13 + 8)/21
= 34/21

B = (1 - 1/5)(1 - 2/5)(1 - 3/5)...(1 - 9/5)
= (4/5)(3/5)(2/5)(1/5)(0/5)(-1/5)(-2/5)(-3/5)(-4/5)
= 0

C = (1 - 1/2)(1 - 1/3)(1 - 1/4)...(1 - 1/50)
= (1/2)(2/3)(3/4)(4/5)...(49/50)
= 1/50

D = (2^2/1.3) * (3^2/2.4) * (4^2/3.5) * (5^2/4.6) * (6^2/5.7)
= (4/3) * (9/8) * (16/15) * (25/23) * (36/35)
= 0.979

30 tháng 4 2017

\(\dfrac{22}{7}\cdot\dfrac{-2}{11}+\dfrac{3}{2}\cdot\dfrac{4}{9}:\left(-4\right)^2\\ =\dfrac{22}{7}\cdot\dfrac{-2}{11}+\dfrac{3}{2}\cdot\dfrac{4}{9}:16\\ =\dfrac{22}{7}\cdot\dfrac{-2}{11}+\dfrac{3}{2}\cdot\dfrac{4}{9}\cdot\dfrac{1}{16}\\ =\dfrac{-4}{7}+\dfrac{2}{3}\cdot\dfrac{1}{16}\\ =\dfrac{-4}{7}+\dfrac{1}{24}\\ =\dfrac{-96}{168}+\dfrac{7}{168}\\ =\dfrac{91}{168}\)

30 tháng 4 2017

Bạn làm sai rồi.

\(\dfrac{22}{7}.\dfrac{-2}{11}=\dfrac{-4}{7}\) chứ ko phải bằng \(\dfrac{4}{7}\) .

22 tháng 10 2017

gfgdjgbhfgbjbfdgbhjdgfhdgfd

22 tháng 8 2019

lớp 1 mà cậu

22 tháng 8 2019

4.24.52-(33.18+33.12)

=4.24.25-[27.(18+12)]

=(4.25).24-[27.30]

=100.24-810

=2400-810

=1590

13 tháng 8 2015

Jang Ha Na làm sai nhé!!!

14 tháng 2 2020

\(C=...\)

\(=\frac{1}{3^2}+\frac{1}{4^2}-\frac{1}{4^2}+\frac{1}{5^2}-\frac{1}{5^2}+...-\frac{1}{14^2}+\frac{1}{14^2}-\frac{1}{15^2}\)

\(=\frac{1}{3^2}-\frac{1}{15^2}\)

\(=\frac{1}{9}-\frac{1}{225}\)

Do \(\frac{1}{9}-\frac{1}{225}\)<\(\frac{1}{5}\)

\(=>C< \frac{1}{5}\)( ĐPCM )

14 tháng 2 2020

C = ...

=> C = \(\frac{1}{3^2}-\frac{1}{4^2}+\frac{1}{4^2}-\frac{1}{5^2}+...+\frac{1}{14^2}-\frac{1}{15^2}\)

C = \(\frac{1}{3^2}-\frac{1}{15^2}\)

Ta thấy : \(\frac{1}{3^2}< \frac{1}{5}\Leftrightarrow\frac{1}{3^2}-\frac{1}{15^2}< \frac{1}{5}\)

=> C < \(\frac{1}{5}\)

14 tháng 6 2023

\(\left(-\dfrac{1}{2}\right)^2\div\dfrac{1}{4}-2\times\left(-\dfrac{1}{2}\right)^2\\= \dfrac{1}{4}\div\dfrac{1}{4}-2\times\dfrac{1}{4}\\ =1-\dfrac{1}{2}\\ =\dfrac{1}{2}\)

\(\left(-2\right)^3\times-\dfrac{1}{24}+\left(\dfrac{4}{3}-1\dfrac{5}{6}\right)\div\dfrac{5}{12}\)

=  \(-6\times-\dfrac{1}{24}+\left(\dfrac{4}{3}-\dfrac{11}{6}\right)\div\dfrac{5}{12}\)

=  \(\dfrac{1}{4}+-\dfrac{1}{2}\div\dfrac{5}{12}\)

=  \(\dfrac{1}{4}+-\dfrac{6}{5}\)

=  \(\dfrac{1}{4}-\dfrac{6}{5}\)

=  \(-\dfrac{19}{20}\)

\(\left(6\dfrac{4}{9}+\dfrac{7}{11}\right)-\left(4\dfrac{4}{9}-2\dfrac{4}{11}\right)\\ =\dfrac{58}{9}+\dfrac{7}{11}-\dfrac{40}{9}+\dfrac{26}{11}\\ =\dfrac{58}{9}-\dfrac{40}{9}+\dfrac{7}{11}+\dfrac{26}{11}\\ =12+3\\ =15\)

14 tháng 6 2023

\(a,\left(\dfrac{-1}{2}\right)^2:\dfrac{1}{4}-2\left(-\dfrac{1}{2}\right)^2\)

\(=\left(-\dfrac{1}{2}\right)^2\left(4-2\right)\)

\(=\dfrac{1}{4}.2=\dfrac{1}{2}\)

\(b,\left(-2\right)^3.\dfrac{-1}{24}+\left(\dfrac{4}{3}-1\dfrac{5}{6}\right):\dfrac{5}{12}\)

\(=\left(-8\right).\dfrac{-1}{24}+\left(-\dfrac{1}{2}\right).\dfrac{12}{5}\)

\(=\dfrac{1}{3}+\left(-\dfrac{1}{5}\right)=\dfrac{2}{15}\)

\(c,\left(6\dfrac{4}{9}+\dfrac{7}{11}\right)-\left(4\dfrac{4}{9}-2\dfrac{4}{11}\right)\)

\(=\dfrac{701}{99}-\dfrac{206}{99}=\dfrac{495}{99}=5\)

\(d,10\dfrac{1}{5}-5\dfrac{1}{2}.\dfrac{60}{11}+\dfrac{3}{15\%}\)

\(=\dfrac{51}{5}-30+20=\dfrac{1}{5}\)

\(e,\dfrac{5}{7}.\dfrac{5}{11}+\dfrac{5}{7}.\dfrac{2}{11}-\dfrac{5}{7}.\dfrac{14}{11}\)

\(=\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}.\left(-\dfrac{7}{11}\right)\)

\(=-\dfrac{5}{11}\)

\(f,\dfrac{-5}{7}.\dfrac{2}{11}+\left(-\dfrac{5}{7}\right).\dfrac{9}{11}+1\dfrac{5}{7}\)

\(=\left(-\dfrac{5}{7}\right)\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{12}{7}\)

\(=\left(-\dfrac{5}{7}\right)+\dfrac{12}{7}=1\)

12 tháng 11 2017

a, (-0.25) * 7.9 * 40 = [ (-0.25) * 40] * 7.9 = -10 * 7.9 = -79

b, ( 3/2 )^3 * 2^3 = ( 3/2*2) ^3 = 3^3 = 27

c, (1.75 / \(\frac{7}{2}\)) * \(\frac{4}{5}\)= ( 7/4 * 7/2 ) *4/5 = \(\frac{49}{10}\)

d, \(\frac{11}{2}\cdot4\frac{5}{3}-2\frac{5}{3}\cdot\frac{11}{2}\)\(\frac{11}{2}\cdot\left(\frac{17}{3}-\frac{11}{3}\right)\)\(\frac{11}{2}\cdot\frac{6}{3}\)\(\frac{11}{2}\cdot2\)=11

21 tháng 4 2018

à, mình tự giải được rồi nhé. hihi