a) \(\frac{1}{8} + \frac{11}{16} = \frac{2}{16} + \frac{11}{16} = \frac{13}{16}\)
б) \(3\frac{5}{12} + 2\frac{3}{8} = 3 + 2 + \frac{5}{12} + \frac{3}{8} = 5 + \frac{10}{24} + \frac{9}{24} = 5 + \frac{19}{24} = 5\frac{19}{24}\)
в) \(\frac{12}{15} + 4\frac{42}{45} = \frac{36}{45} + 4\frac{42}{45} = 4 + \frac{36+42}{45} = 4 + \frac{78}{45} = 4 + 1\frac{33}{45} = 5\frac{11}{15}\)