Given:
[tex]\frac{12}{13}+(-\frac{1}{13})[/tex]Adding a negativen number is the same as subtracting that number, so:
[tex]\frac{12}{13}-\frac{1}{13}[/tex]Since both denominators (bottom number ) are equal we can subtract the numerators ( top numbers)
[tex]\frac{(12-1)}{13}=\frac{11}{13}[/tex]Answer:
[tex]\frac{11}{13}[/tex]