To solve this expression, we can simplify each term separately and then add them together.

First, let's simplify the first term: 4/9 chia (-1/7)

To multiply fractions, we multiply the numerators together and the denominators together:
4/9 chia (-1/7) = (4 * -1) / (9 * 7) = -4/63

Now, let's simplify the second term: 6 5/9 chia (-1/7)

To add a whole number with a fraction, we convert the whole number into a fraction by multiplying it by the denominator of the fraction and adding the numerator. Then we add the fractions together.
6 5/9 chia (-1/7) = (6 * 9 + 5) / 9 chia (-1/7) = (54 + 5) / 9 chia (-1/7) = 59/9 chia (-1/7)

Now, let's add the two simplified terms together:
-4/63 + 59/9 chia (-1/7)

To add fractions, we need to have a common denominator. The least common multiple of 63, 9, and 7 is 441. So, we need to convert both fractions to have a denominator of 441.

-4/63 = (-4 * 7) / (63 * 7) = -28/441
59/9 = (59 * 49) / (9 * 49) = 2891/441

Now, we can add the fractions together:
-28/441 + 2891/441 chia (-1/7)

Since the denominators are the same, we can add the numerators directly:
-28/441 + 2891/441 = (2891 - 28) / 441 = 2863/441

Therefore, the final answer is 2863/441 chia (-1/7).