To make the expression \( 18 - 9 \frac{4}{9} + \frac{7}{9} + 8 \) easiest to add, we should look for combinations that simplify the calculations.
Let's break it down:
- Combine whole numbers: \( 18 \) and \( 8 \).
- Handle the fractions, which are \( -9 \frac{4}{9} + \frac{7}{9} \).
We can group it as follows:
\[ (18 - 8) + (-9 \frac{4}{9} + \frac{7}{9}) \]
This simplifies to:
- Grouping the whole numbers gives \( 10 \).
- Now, for the fraction \( -9 \frac{4}{9} + \frac{7}{9} \), convert \( -9 \frac{4}{9} \) to its improper fraction, which is \( -\frac{85}{9} \).
So the operation becomes:
\[ 10 - \frac{85}{9} + \frac{7}{9} \]
This grouping allows you to first simplify the numbers, making the fraction addition slightly less confusing afterward.
Thus, the best grouping for adding in the expression is:
\[ (18 - 8) + (-9 \frac{4}{9} + \frac{7}{9}) \]
Which is clear and straightforward to evaluate. So the answer from your options is: (18 - 8) + (-9 \frac{4}{9} + \frac{7}{9}).