Вычислите: 1) -43 + (-60) + 18 + 36 + (-19); 2) -2,43 + 6,31 + (-3,21) + 0,49 + 4,87; 3) - 19/42 + (-9/16) + (-11/42) + 5/16

1) -43 + (-60) + 18 + 36 + (-19)= -43-60+18+36-19= -68;  2) -2,43 + 6,31 + (-3,21) + 0,49 + 4,87= -2,43+6,31-3,21+0,49+4,87= 6,03;  3) [latex]- \frac{19}{42} +(- \frac{9}{16})+(- \frac{11}{42} )+ \frac{5}{16} =- \frac{19}{42}- \frac{11}{42} - \frac{9}{16}+ \frac{5}{16} =[/latex][latex]- \frac{30}{42} - \frac{4}{16} =- \frac{15}{21} - \frac{1}{4} =- (\frac{4*15+21}{84} )=- \frac{81}{84} =- \frac{27}{28} [/latex]