a)
[tex]2 \times \frac{15}{17} + 6 \times \frac{4}{19} + \frac{15}{19} = 2 \times \frac{15}{17} + 7 = 9 \times \frac{15}{17} [/tex]
b)
[tex]0.25 + 1 \times \frac{7}{8} + 0.75 = 1 + 1 \times \frac{7}{8} = 2 \times \frac{7}{8} [/tex]
c)
[tex]21 \times \frac{1}{4} + 2.49 + 1.21 = 3.7 + 21.25 = 24.95[/tex]
