The following are math problems written on a chalkboard. Please transcribe them as JSON.

Problem a)

\[ \left( 7 - 2 \frac{18}{23} \cdot 1 \frac{11}{12} + 2 \frac{1}{8} \cdot \frac{4}{17} \right) : 1.5 - \frac{4}{5} = \frac{29}{45} \]

Problem b)

\[ \frac{3}{32} \cdot 3 \frac{1}{5} : \left( 2 \frac{1}{2} \cdot \frac{1}{30} - ​ \right) : 7 \frac{1}{3} = \]

Problem 3)

\[ 4 - 5 \frac{1}{3} = 6 \frac{2}{7} - 5 \frac{1}{3} = 1 \frac{2}{3} \]

Problem 6)

\[ \frac{5}{13} - \frac{9}{5} = \frac{65 - 36}{45} \]

\[ = \frac{29}{45} \]