Найдите значение суммы: 1)-4+(-7) = 2)-0,46+(-0,89) 3)-2,3+(-0,86)...

1) -4-7=-11
2) -0,46-0,89=-1,35
3) -2,3-0,86=3,16
4) $-5 \frac{7}{9} -3 \frac{4}{9}= -8( \frac{7}{9}+ \frac{4}{9})=-8 \frac{11}{9}=-7 \frac{3}{9}=-7 \frac{1}{3}$
5) $- \frac{5}{8}- \frac{11}{12} =- \frac{5*4+11*2}{24} =- \frac{20+22}{24}=- \frac{42}{24}=-1 \frac{18}{24} =-1 \frac{3}{4}$
6) $-4 \frac{5}{14} -7 \frac{9}{21} =-11(\frac{5}{14} + \frac{3}{7})=-11 \frac{5+3*2}{14} =-11 \frac{11}{14}$