2.245 Найдите значение выражения: 1) 85 × 1234 – 5625 : 75 – 159758 : 529; 2) 4225 : 65 + 75 × 2454 – 330078 : 813. 2.246 Найдите сумму: a) $$38\frac{1}{8}+4\frac{5}{24}$$; б) $$4\frac{19}{75}+6\frac{17}{45}$$; в) $$47\frac{3}{14}+1\frac{8}{21}$$; г) $$54\frac{3}{4}+18\frac{5}{6}$$; д) $$28\frac{1}{9}+13\frac{3}{4}$$; ж) $$9\frac{3}{11}+2\frac{2}{9}$$; з) $$3\frac{11}{24}+\frac{1}{6}$$

2.245 1) Выполним действия по порядку: * $$85\cdot1234 = 104890$$ * $$5625 \div 75 = 75$$ * $$159758 \div 529 = 302$$ * $$104890 - 75 - 302 = 104513$$ Ответ: 104513 2) Выполним действия по порядку: * $$4225 \div 65 \approx 65$$ * $$75 \cdot 2454 = 184050$$ * $$330078 \div 813 = 406$$ * $$65 + 184050 - 406 = 183709$$ Ответ: 183709 2.246 a) $$38\frac{1}{8}+4\frac{5}{24} = 38\frac{3}{24}+4\frac{5}{24} = (38+4)+(\frac{3}{24}+\frac{5}{24}) = 42+\frac{8}{24} = 42\frac{1}{3}$$ Ответ: $$42\frac{1}{3}$$ б) $$4\frac{19}{75}+6\frac{17}{45} = 4\frac{57}{225}+6\frac{85}{225} = (4+6)+(\frac{57}{225}+\frac{85}{225}) = 10+\frac{142}{225} = 10\frac{142}{225}$$ Ответ: $$10\frac{142}{225}$$ в) $$47\frac{3}{14}+1\frac{8}{21} = 47\frac{9}{42}+1\frac{16}{42} = (47+1)+(\frac{9}{42}+\frac{16}{42}) = 48+\frac{25}{42} = 48\frac{25}{42}$$ Ответ: $$48\frac{25}{42}$$ г) $$54\frac{3}{4}+18\frac{5}{6} = 54\frac{9}{12}+18\frac{10}{12} = (54+18)+(\frac{9}{12}+\frac{10}{12}) = 72+\frac{19}{12} = 72 + 1\frac{7}{12} = 73\frac{7}{12}$$ Ответ: $$73\frac{7}{12}$$ д) $$28\frac{1}{9}+13\frac{3}{4} = 28\frac{4}{36}+13\frac{27}{36} = (28+13)+(\frac{4}{36}+\frac{27}{36}) = 41+\frac{31}{36} = 41\frac{31}{36}$$ Ответ: $$41\frac{31}{36}$$ ж) $$9\frac{3}{11}+2\frac{2}{9} = 9\frac{27}{99}+2\frac{22}{99} = (9+2)+(\frac{27}{99}+\frac{22}{99}) = 11+\frac{49}{99} = 11\frac{49}{99}$$ Ответ: $$11\frac{49}{99}$$ з) $$3\frac{11}{24}+\frac{1}{6} = 3\frac{11}{24}+\frac{4}{24} = 3+\frac{15}{24} = 3\frac{5}{8}$$ Ответ: $$3\frac{5}{8}$$