Контрольная работа «Сложение и вычитание положительных и отрицательных чисел». Вариант 2. №1. Днем температура равнялась 5 градусам, а к вечеру понизилась на 8 градусов. Какую температуру показывал термометр вечером? №2. На балансе карты у Валентины Семёновны было -14 562 рубля. Она положила на карту 20 000 рублей. Какой баланс карта показывает теперь? №3. Вычислите: 1) - 14 + 9; 2) 28 + (-5); 3)-21-16; 4)19(-81); 5)2,5-1,9; 6) -3/16 + 5/12; 7)-10/11 - (-10/11); 8)1 2/9 +(-11/27) №4. Решите уравнения: 1) 21 + x = 8; 2) x 4,5-8,8; 3)11,8x = -4,6. №5. Вычислите: 1) 13/30-(-1/6)+(-7/10)-11/15; 2) -(-1/2)-47/50-2/5+(-3/10): 3) 23/44-1/2+3/4+31/88+9/11; 4) -13/46-3/4-61/120+11/30-7/12

-\(\frac{3}{16}\) + \(\frac{5}{12}\) = -\(\frac{3 \cdot 3}{16 \cdot 3}\) + \(\frac{5 \cdot 4}{12 \cdot 4}\) = -\(\frac{9}{48}\) + \(\frac{20}{48}\) = \(\frac{11}{48}\)

-\(\frac{10}{11}\) - (-\(\frac{10}{11}\)) = -\(\frac{10}{11}\) + \(\frac{10}{11}\) = 0

1\(\frac{2}{9}\) + (-\(\frac{11}{27}\)) = \(\frac{11}{9}\) - \(\frac{11}{27}\) = \(\frac{11 \cdot 3}{9 \cdot 3}\) - \(\frac{11}{27}\) = \(\frac{33}{27}\) - \(\frac{11}{27}\) = \(\frac{22}{27}\)

21 + x = 8

x = 8 - 21

x = -13

x - 4,5 = -8,8

x = -8,8 + 4,5

x = -4,3

-11,8 - x = -4,6

-x = -4,6 + 11,8

-x = 7,2

x = -7,2

\(\frac{13}{30}\) - (-\(\frac{1}{6}\)) + (-\(\frac{7}{10}\)) - \(\frac{11}{15}\) = \(\frac{13}{30}\) + \(\frac{1}{6}\) - \(\frac{7}{10}\) - \(\frac{11}{15}\) = \(\frac{13}{30}\) + \(\frac{5}{30}\) - \(\frac{21}{30}\) - \(\frac{22}{30}\) = \(\frac{13 + 5 - 21 - 22}{30}\) = \(\frac{-25}{30}\) = -\(\frac{5}{6}\)

- (-\(\frac{1}{2}\)) - \(\frac{47}{50}\) - \(\frac{2}{5}\) + (-\(\frac{3}{10}\)) = \(\frac{1}{2}\) - \(\frac{47}{50}\) - \(\frac{2}{5}\) - \(\frac{3}{10}\) = \(\frac{25}{50}\) - \(\frac{47}{50}\) - \(\frac{20}{50}\) - \(\frac{15}{50}\) = \(\frac{25 - 47 - 20 - 15}{50}\) = \(\frac{-57}{50}\) = -1\(\frac{7}{50}\)

\(\frac{23}{44}\) - \(\frac{1}{2}\) + \(\frac{3}{4}\) + \(\frac{31}{88}\) + \(\frac{9}{11}\) = \(\frac{46}{88}\) - \(\frac{44}{88}\) + \(\frac{66}{88}\) + \(\frac{31}{88}\) + \(\frac{72}{88}\) = \(\frac{46 - 44 + 66 + 31 + 72}{88}\) = \(\frac{171}{88}\) = 1\(\frac{83}{88}\)

- \(\frac{13}{46}\) - \(\frac{3}{4}\) - \(\frac{61}{120}\) + \(\frac{11}{30}\) - \(\frac{7}{12}\) = -\(\frac{195}{690}\) - \(\frac{517.5}{690}\) - \(\frac{351.5}{690}\) + \(\frac{253}{690}\) - \(\frac{402.5}{690}\) = \(\frac{-195 - 517.5 - 351.5 + 253 - 402.5}{690}\) = \(\frac{-1213.5}{690}\) = -1\(\frac{523.5}{690}\)