423. Найдите значения сумм: 1) 1/10 + 9/100; 2) 27/100 + 7/10; 3) 4/5 + 7/10; 4) 2/3 + 5/9; 5) 15/24 + 1/6; 6) 5/9 + 2/27.

1. Приведём к знаменателю 100: \(\frac{1}{10}+\frac{9}{100}=\frac{10}{100}+\frac{9}{100}=\frac{19}{100}\).
2. \(\frac{27}{100}+\frac{7}{10}=\frac{27}{100}+\frac{70}{100}=\frac{97}{100}\).
3. \(\frac{4}{5}+\frac{7}{10}=\frac{8}{10}+\frac{7}{10}=\frac{15}{10}=\frac{3}{2}\).
4. \(\frac{2}{3}+\frac{5}{9}=\frac{6}{9}+\frac{5}{9}=\frac{11}{9}\).
5. \(\frac{15}{24}+\frac{1}{6}=\frac{15}{24}+\frac{4}{24}=\frac{19}{24}\).
6. \(\frac{5}{9}+\frac{2}{27}=\frac{15}{27}+\frac{2}{27}=\frac{17}{27}\).

Ответ: 1) 19/100; 2) 97/100; 3) 3/2; 4) 11/9; 5) 19/24; 6) 17/27.