Write the negative (additive) inverse of $-1$.

Using commutativity and associativity of addition of rational numbers, express the following as a rational number:

$\frac{2}{5}+\frac{7}{3}+\frac{-4}{5}+\frac{-1}{3}$

Using commutativity and associativity of addition of rational numbers, express the following as a rational number:

$\frac{3}{7}+\frac{-4}{9}+\frac{-11}{7}+\frac{7}{9}$

Using commutativity and associativity of addition of rational numbers, express the following as a rational number

$\frac{2}{5}+\frac{8}{3}+\frac{-11}{15}+\frac{4}{5}+\frac{-2}{3}$

Using commutativity and associativity of addition of rational numbers, express the following as a rational number

$\frac{4}{7}+0+\frac{-8}{9}+\frac{-13}{7}+\frac{17}{21}$

Re-arrange suitably and find the sum in each of the following:

$\frac{11}{12}+\frac{-17}{3}+\frac{11}{2}+\frac{-25}{2}$

Re-arrange suitably and find the sum in the following

$\frac{-6}{7}+\frac{-5}{6}+\frac{-4}{9}+\frac{-15}{7}$

Re-arrange suitably and find the sum in the following

$\frac{3}{5}+\frac{7}{3}+\frac{9}{5}+\frac{-13}{15}+\frac{-7}{3}$

Re-arrange suitably and find the sum in the following:

$\frac{4}{13}+\frac{-5}{8}+\frac{-8}{13}+\frac{9}{13}$