Question

(-2/3)+(-3/4)-1/5-(-1)=
(1/2-3/4)-(5/2-5/4)-(3/2-3/4)=
(-2/3+4/5+1)-(-4/3+2/5-2)+(-2+5/3)=
(1-3/4+2/3)-(1-5/3+1/4)-(1-4/3-3/4)=
(-2/3)*(6/5)+1/2*(-4/3)-(-2)*3/10=
1/2(1/3+1/4-1/5)=
2/3-(2 1/2-1 1/4)=
0,1-[3/2-(0,5+0,4)]=
(1/2-1/3)*(1/2+1/3)*(-1)=
(-4)*(-3/8-3/8*5/3)=
0,8*(0,75-1/4)*(-2)
(78-252,001)*(-1000)=
VA ROG AJUTATI-MA! 

Answer 1

$1).(- \frac{2}{3} )+(- \frac{3}{4}) - \frac{1}{5} -(-1)=- \frac{8}{12} +(- \frac{9}{12} )- \frac{1}{5} -(- \frac{12}{12} )= \\ =(- \frac{17}{12} )- \frac{1}{5} =(- \frac{85}{60} )- \frac{12}{60} =- \frac{97}{60}$
$2). ( \frac{1}{2} - \frac{3}{4} )-( \frac{5}{2} - \frac{5}{4} )-( \frac{3}{2} - \frac{3}{4} )=( \frac{2}{4} - \frac{3}{4} )-( \frac{10}{4} - \frac{5}{4} )-( \frac{6}{4} - \frac{3}{4})= \\ =(- \frac{1}{4} )- \frac{5}{4} - \frac{3}{4} =- \frac{9}{4}$
$3).(- \frac{2}{3} + \frac{4}{5} +1)-(- \frac{4}{3} + \frac{2}{5} -2)+(-2+ \frac{5}{3} )= \\ =(- \frac{10}{15} + \frac{12}{15} + \frac{15}{15} )-(- \frac{20}{15} + \frac{6}{15} - \frac{30}{15} )+(- \frac{30}{15} + \frac{25}{15} )= \\ = \frac{17}{15} -(- \frac{44}{15} )+(- \frac{5}{15} )= \frac{56}{15}$
$4).(1- \frac{3}{4} + \frac{2}{3} )-(1- \frac{5}{3} + \frac{1}{4} )-(1- \frac{4}{3} - \frac{3}{4} )= \\ =( \frac{12}{12} - \frac{9}{12} + \frac{8}{12} )-( \frac{12}{12} - \frac{20}{12} + \frac{3}{12} )-( \frac{12}{12} - \frac{16}{12} - \frac{9}{12} )= \\ = \frac{11}{12} -(- \frac{5}{12} )-(- \frac{13}{12} )= \frac{29}{12}$
$5).(- \frac{2}{3} )*\frac{6}{5} + \frac{1}{2} *(- \frac{4}{3} )-(-2)* \frac{3}{10} =(- \frac{12}{15} )+(- \frac{4}{6} )-(- \frac{6}{10} )= \\ = (-\frac{48}{60} )+(- \frac{40}{60} )-(- \frac{36}{60} )=- \frac{52}{60}$
$6). \frac{1}{2} ( \frac{1}{3} + \frac{1}{4} - \frac{1}{5} )= \frac{1}{2} ( \frac{20}{60} + \frac{15}{60} - \frac{12}{60} )= \frac{1}{2} * \frac{23}{60} = \frac{23}{120}$
$7). \frac{2}{3} -( 2 \frac{1}{2} -1 \frac{1}{4} )= \frac{2}{3} -( \frac{5}{2} - \frac{5}{4} )= \frac{2}{3} -( \frac{10}{4} - \frac{5}{4} )= \frac{2}{3} - \frac{5}{4} = \\ = \frac{8}{12} - \frac{15}{12} =- \frac{7}{12}$
$8).0,1-[ \frac{3}{2} -(0,5+0,4)]=0,1-[1,5-(0,5+0,4)]= \\ =0,1-(1,5-0,9)=0,1-0,6=-0,5$
$9).( \frac{1}{2}- \frac{1}{3} )*( \frac{1}{2} + \frac{1}{3} )*(-1)=( \frac{3}{6} - \frac{2}{6} )*( \frac{3}{6} + \frac{2}{6} )*(-1)= \\ = \frac{1}{6} * \frac{5}{6} *(-1)= \frac{5}{36} *(-1)=- \frac{5}{36}$
$10).(-4)*(- \frac{3}{8} - \frac{3}{8} * \frac{5}{3} )=(-4)*(- \frac{3}{8} - \frac{15}{24} )=(-4)*(- \frac{9}{24} - \frac{15}{24} )= \\ =(-4)*(- \frac{24}{24} )=(-4)*(-1)=4$
$11).0,8*(0,75- \frac{1}{4} )*(-2)=0,8*(0,75-0,25)*(-2)= \\ =0,8*0,5*(-2)=0,4*(-2)=-0,8$
$12).(78-252,001)*(-1000)=(-174,001)*(-1000)=174001$