Question

6 4/9+3 5/9
1-3/11
1- 13/ 40

Answer 1

$6 \frac{4}{9} +3 \frac{5}{9} =(6+3)+( \frac{4}{9} + \frac{5}{9} )=9+ \frac{9}{9} =9+1=10 \\ \\ 1- \frac{3}{11} = \frac{11}{11} - \frac{3}{11} = \frac{8}{11} \\ \\ 1- \frac{13}{40} = \frac{40}{40} - \frac{13}{40} = \frac{27}{40}$