To find two numbers from the list whose sum is -2.6, we first write -2.6 as a fraction. The decimal -2.6 can be expressed as a fraction:
\[ -2.6 = -\frac{26}{10} = -\frac{13}{5} \]
Now we will convert the other numbers in the list to fractions for easier comparison:
- \(0.7 = \frac{7}{10}\)
- \(1.0 = \frac{10}{10} = 1\)
- \(0.8 = \frac{8}{10} = \frac{4}{5}\)
- \(-3 \frac{3}{10} = -\frac{33}{10}\)
- \(-3 \frac{2}{5} = -\frac{17}{5}\)
- \(-\frac{18}{5}\)
Next, we can check combinations of these numbers:
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Combining \(0.7\) and \(-3 \frac{3}{10}\): \[ \frac{7}{10} + -\frac{33}{10} = \frac{7 - 33}{10} = -\frac{26}{10} = -2.6 \quad \text{(This works!)} \]
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Check combinations with \(-3 \frac{2}{5}\) and \(-\frac{18}{5}\) to see if they can pair with another number to yield a sum of -2.6.
After testing, we find the two numbers:
\[ 0.7 \quad \text{and} \quad -3 \frac{3}{10} (or , -\frac{33}{10}) \]
These two numbers sum to -2.6. Thus, the answer is \(0.7\) and \(-3 \frac{3}{10}\).