Lời giải:

$A=(1-4)+(7-10)+(13-16)+....+(97-100)+103$

$=\underbrace{(-3)+(-3)+(-3)+...+(-3)}_{17}+103$

$=(-3).17+103=52$

a) 152 + (-73) - (-18) - 127 = 152 – 73 +18 -127

= (152 + 18) – (127 + 73) = 170 - 200 = -(200 - 170) = -30

b) 7 + 8 + (-9)  + (-10) = (7 + 8) + [(-9)  + (-10)]

= 15 + (-19) = -(19 - 15) = -4.

1: \(\dfrac{1}{2}+\dfrac{9}{10}+\dfrac{5}{6}-\dfrac{11}{14}-\dfrac{1}{3}+\dfrac{-4}{35}\)

\(=\left(\dfrac{1}{2}+\dfrac{5}{6}-\dfrac{1}{3}\right)+\dfrac{9}{10}-\left(\dfrac{11}{14}+\dfrac{4}{35}\right)\)

\(=\dfrac{3+5-2}{6}+\dfrac{9}{10}-\dfrac{55+8}{70}\)

\(=1+\dfrac{9}{10}-\dfrac{9}{10}\)

=1

\(a)\left(-17\right)+\left(-23\right)+44=-40+44=4\)

\(b)\left(-39\right)+\left(-16\right)+39=\left[\left(-39\right)+39\right]+\left(-16\right)=0+\left(-16\right)=-16\)

a) (- 17) + (- 23) + 44;

= (- 40) + 44

= 4

b) (- 39) + (- 16) + 39.

= (- 39) + 39 + (- 16)

= 0 + (- 16)

= - 16

a) (- 17) + (- 23) + 44

=  [ (- 17) + (- 23) ] + 44 

=  (- 40) + 44

= 4

b) (- 39) + (- 16) + 39

= [ (- 39) + 39 ] + (- 16)

= 0 + (- 16)

= -16

a) 21 - 22 + 23 - 24

= (21 - 22) + (23 - 24)

= (-1) + (-1)  = -2

b) 125 - (115 - 99)

= 125 - 115 + 99

= (125 - 115) + 99

 = 10 + 99 = 109.

mik làm 1 câu thôi các cau khác 1 chang lun chỉ khác số 

A = 1 + (-2) + 3 + (-4) + 5 +(-6) + ... + 99 + (-100)

A=(1+(-2))+(3+(-4))+.....+(99+(-100))

A=(-1)+(-1)+......+(-1) CÓ 50 SỐ 

A= -50

\(a.21-22+23-24\)

\(=\left(-1\right)+\left(-1\right)=-2\)

\(b.125-\left(115-99\right)\)

\(=125-16=109\)

21-22+23-24

= (-1)+(-1)

=-2

125-(115-99)

= 125-16

=109

a)

 \(\begin{array}{l}\frac{4}{{15}} - \left( {2,9 - \frac{{11}}{{15}}} \right)\\ = \frac{4}{{15}} - 2,9 + \frac{{11}}{{15}}\\ = \left( {\frac{4}{{15}} + \frac{{11}}{{15}}} \right) - 2,9\\=\frac{15}{15}-2,9 \\= 1 - 2,9 =  - 1,9\end{array}\)

b)

\(\begin{array}{l}( - 36,75) + \left( {\frac{{37}}{{10}} - 63,25} \right) - ( - 6,3)\\ = ( - 36,75) + 3,7 - 63,25 + 6,3\\ = \left( { - 36,75 - 63,25} \right) + \left( {3,7 + 6,3} \right)\\ =  - 100 + 10 =  - 90\end{array}\)

c)

\(\begin{array}{l}6,5 + \left( { - \frac{{10}}{{17}}} \right) - \left( { - \frac{7}{2}} \right) - \frac{7}{{17}}\\ = \frac{{65}}{{10}} - \frac{{10}}{{17}} + \frac{7}{2} - \frac{7}{{17}}\\ = \left( {\frac{{65}}{{10}} + \frac{7}{2}} \right) - \left( {\frac{{10}}{{17}} + \frac{7}{{17}}} \right)\\ = \left( {\frac{{65}}{{10}} + \frac{{35}}{{10}}} \right) - \frac{17}{17}\\ = \frac{100}{10}-1\\=10 - 1 = 9\end{array}\)

d)

\(\begin{array}{l}( - 39,1) \cdot \frac{{13}}{{25}} - 60,9 \cdot \frac{{13}}{{25}}\\ = \frac{{13}}{{25}}.\left( { - 39,1 - 60,9} \right)\\ = \frac{{13}}{{25}}.\left( { - 100} \right)\\ =  - 52\end{array}\).

a)

\(\begin{array}{l}\frac{{ - 3}}{{10}} - 0,125 + \frac{{ - 7}}{{10}} + 1,125 \\= \left( {\frac{{ - 3}}{{10}} + \frac{{ - 7}}{{10}}} \right) + \left( {1,125 - 0,125} \right)\\ =  - 1 + 1 \\= 0\end{array}\)       

b)

\(\begin{array}{l}\frac{{ - 8}}{3}.\frac{2}{{11}} - \frac{8}{3}:\frac{{11}}{9} \\= \frac{8}{3}.\frac{{ - 2}}{{11}} - \frac{8}{3}.\frac{9}{{11}}\\ = \frac{8}{3}.\left( {\frac{{ - 2}}{{11}} - \frac{9}{{11}}} \right)\\ =\frac{{ - 8}}{3}.\frac{-11}{11}\\= \frac{8}{3}.\left( { - 1} \right) \\= \frac{{ - 8}}{3}\end{array}\)

b: 15p=0,25h

Độ dài quãng đường AB là:

\(30\cdot0,25=7,5\left(km\right)\)

a: \(A=\dfrac{7}{12}+\dfrac{-23}{30}+\dfrac{5}{12}+\dfrac{-37}{30}\)

\(=\left(\dfrac{7}{12}+\dfrac{5}{12}\right)+\left(-\dfrac{23}{30}-\dfrac{37}{30}\right)\)

\(=1-2=-1\)