276. Найдите сумму: 1) 4 5/9 + 7 1/6; 2) 6 11/12 + 8 13/18; 3) 2 3/16 + 1 7/24 + 3 1/12.

Решение:

1. \( 4 \frac{5}{9} + 7 \frac{1}{6} = \frac{41}{9} + \frac{43}{6} = \frac{82}{18} + \frac{129}{18} = \frac{211}{18} = 11 \frac{13}{18} \)
2. \( 6 \frac{11}{12} + 8 \frac{13}{18} = \frac{83}{12} + \frac{157}{18} = \frac{249}{36} + \frac{314}{36} = \frac{563}{36} = 15 \frac{23}{36} \)
3. \( 2 \frac{3}{16} + 1 \frac{7}{24} + 3 \frac{1}{12} = \frac{35}{16} + \frac{31}{24} + \frac{37}{12} = \frac{105}{48} + \frac{62}{48} + \frac{148}{48} = \frac{315}{48} = \frac{105}{16} = 6 \frac{9}{16} \)

Ответ: 1) \( 11 \frac{13}{18} \); 2) \( 15 \frac{23}{36} \); 3) \( 6 \frac{9}{16} \).