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20 tháng 12 2018

\(\left[504-\left(5^2.8+70\right):3^3+6\right]:25\)

\(\left[504-\left(25.8+70\right):27+6\right]:25\)

\(\left[504-\left(200+70\right):27+6\right]:25\)

\(\left[504-270:27+6\right]:25\)

\(\left[504-10+6\right]:25\)

\(\left[494+6\right]:25\)

\(500:25\)

= 20

20 tháng 12 2018

\(\left[504-(5^2\cdot8+70):3^3+6\right]:25\)

\(=\left[504-(25\cdot8+70):27+6\right]:25\)

\(=\left[504-(200+70):27+6\right]:25\)

\(=\left[504-270:27+6\right]:25\)

\(=\left[504-10+6\right]:25\)

\(=\left[494+6\right]:25\)

\(=500:25=20\)

\(\text{Ko chắc }:)\)

a: \(5\cdot\frac{5}{27}+\frac{7}{23}+0,5\cdot\frac57+\frac{16}{23}+\frac12\)

\(=5\cdot\frac{5}{27}+\left(\frac{7}{23}+\frac{16}{23}\right)+0,5\left(\frac57+1\right)\)

\(=\frac{25}{27}+1+0,5\cdot\frac{12}{7}=\frac{25}{27}+1+\frac67=\frac{25}{27}+\frac{13}{7}=\frac{526}{27\cdot7}=\frac{526}{189}\)

b: \(25\frac16:\frac{-4}{5}-45\frac16:\frac{-4}{5}\)

\(=\left(25+\frac16-45-\frac16\right):\frac{-4}{5}\)

\(=-20\cdot\frac{-5}{4}=25\)

c: \(25\cdot\left(-\frac15\right)^3+\frac15-2\cdot\left(-\frac12\right)^2-\frac12\)

\(=25\cdot\frac{-1}{125}+\frac15-2\cdot\frac14-\frac12\)

\(=-\frac15+\frac15-\frac12-\frac12=-1\)

a: \(-\left(251\cdot3+281\right)+3\cdot251-\left(1-281\right)\)

\(=-251\cdot3-281+3\cdot251-1+281\)

=-1

b: \(\left(0,75-\frac14\right):\left(-5\right)+\frac{1}{15}-\left(-\frac15\right):\left(-3\right)\)

\(=\left(0,75-0,25\right):\left(-5\right)+\frac{1}{15}-\frac{1}{15}\)

=0,5:(-5)

=-1

c: \(\sqrt{\frac{4}{81}}:\sqrt{\frac{25}{81}}-1\frac25\)

\(=\frac29:\frac59-\frac75\)

\(=\frac25-\frac75=-\frac55=-1\)

a: \(-\left(251\cdot3+281\right)+3\cdot251-\left(1-281\right)\)

\(=-251\cdot3-281+3\cdot251-1+281\)

=-1

b: \(\left(0,75-\frac14\right):\left(-5\right)+\frac{1}{15}-\left(-\frac15\right):\left(-3\right)\)

\(=\left(0,75-0,25\right):\left(-5\right)+\frac{1}{15}-\frac{1}{15}\)

=0,5:(-5)

=-1

c: \(\sqrt{\frac{4}{81}}:\sqrt{\frac{25}{81}}-1\frac25\)

\(=\frac29:\frac59-\frac75\)

\(=\frac25-\frac75=-\frac55=-1\)

a: \(5\cdot\frac{5}{27}+\frac{7}{23}+0,5\cdot\frac57+\frac{16}{23}+\frac12\)

\(=5\cdot\frac{5}{27}+\left(\frac{7}{23}+\frac{16}{23}\right)+0,5\left(\frac57+1\right)\)

\(=\frac{25}{27}+1+0,5\cdot\frac{12}{7}=\frac{25}{27}+1+\frac67=\frac{25}{27}+\frac{13}{7}=\frac{526}{27\cdot7}=\frac{526}{189}\)

b: \(25\frac16:\frac{-4}{5}-45\frac16:\frac{-4}{5}\)

\(=\left(25+\frac16-45-\frac16\right):\frac{-4}{5}\)

\(=-20\cdot\frac{-5}{4}=25\)

c: \(25\cdot\left(-\frac15\right)^3+\frac15-2\cdot\left(-\frac12\right)^2-\frac12\)

\(=25\cdot\frac{-1}{125}+\frac15-2\cdot\frac14-\frac12\)

\(=-\frac15+\frac15-\frac12-\frac12=-1\)

13 tháng 9 2016

a) 125 + 70 + 375 + 230 = (125 + 375) + (70 + 230) = 500 + 300 = 800

b) 62 : 4 . 3 + 2 . 52 = 62 : 22 . 3 + 2 . 25 = 32 . 3 + 50 = 33 + 50 = 27 + 50 = 77

c) 150 : [25 . (18 - 42)] = 150 : (25 . 2) = 150 : 50 = 3

30 tháng 12 2021

a) (-124) + 24 = -100
b) 37. 78 + 37. 22
=  37 . ( 78 + 22 )
=  37 . 100
= 3700

 

30 tháng 12 2021

tk cho mik nha

9 tháng 11 2021

\(A=2019^2-\left(2019-3\right)\left(2019+3\right)\\ A=2019-2019^2-2019\cdot3+2019\cdot3+3^2\\ A=9\)

15 tháng 1 2020

a, 47.69-31(-47)

=47(69+31)

=47.100

4700

b,(-14)(-25)+25(-11)

=14.25+25(-11)

=25(14-11)

=25.3=75

20 tháng 12 2018

[ 219 + (-219)] + 12.5

= 0 + 12.5

= 12.5

20 tháng 12 2018

Sai rồi -299 mà