a) (-21) + |-50| + (-29) – |-2016|

= (-21) + 50 + (-29) – 2016

= [(-21) + (-29) + 50] – 2016 = ( -50 +50 ) – 2016

= 0 – 2016 = - 2016 .

b)  36   :   3 2   +   3 2   .   2 3   - 15 0

= 36 : 9 + 9 . 8 – 1 = 4 + 72 – 1 = 76 – 1 = 75

c)  (   5 103   –   5 102   –   5 101 )   :   (   5 99   .   26   –   5 99 )

=  (   5 103   –   5 102   –   5 101 )   :   5 99   .   ( 26   –   1 )

=  (   5 103   –   5 102   –   5 101 )   :   (   5 99   .   25 )

=  5 101   (   5 2   –   5 1   –   5 0 )   :   (   5 99   .   5 2   )

= (   5 101   .   19   )   :   5 101   = 19

a)-21+50-29-2016

=-2016

b) 36:9+9.8-1

=4+72-1

=75

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

Ta có: \(\left(\frac{3}{29}-\frac15\right)\cdot\frac{29}{3}\)

\(=\frac{3}{29}\cdot\frac{29}{3}-\frac15\cdot\frac{29}{3}\)

\(=1-\frac{29}{15}=-\frac{14}{15}\)

− 5 12 − − 3 24 = − 5 12 + 3 24 = − 10 24 + 3 24 = − 7 24

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

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

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