Question

4 5/1+(5 1/2-3 4/21)=

Answer 1

$9 + (5 \frac{1}{2} - 3 \frac{4}{21} ) = \\ \\ = 9 + (5 \frac{21}{42} - 3 \frac{8}{42} ) = \\ \\ = 9 + 2 \frac{13}{42} = 11 \frac{13}{42}$