-3/10 +( - 1 1/2 ) + ( - 4/5 )

To solve the expression \(-\frac{3}{10} + \left(-1 \frac{1}{2}\right) + \left(-\frac{4}{5}\right)\), let's first convert the mixed number into an improper fraction:

\[ -1 \frac{1}{2} = -\frac{3}{2} \]

Now we can rewrite the expression:

\[ -\frac{3}{10} - \frac{3}{2} - \frac{4}{5} \]

Next, we need to find a common denominator. The denominators are 10, 2, and 5. The least common multiple (LCM) of these numbers is 10.

Now, we will convert each term to have a denominator of 10:

1. The first term is already \(-\frac{3}{10}\).
2. For \(-\frac{3}{2}\), multiply the numerator and denominator by 5: \[ -\frac{3}{2} = -\frac{3 \times 5}{2 \times 5} = -\frac{15}{10} \]
3. For \(-\frac{4}{5}\), multiply the numerator and denominator by 2: \[ -\frac{4}{5} = -\frac{4 \times 2}{5 \times 2} = -\frac{8}{10} \]

Now we can add all the fractions together:

\[ -\frac{3}{10} - \frac{15}{10} - \frac{8}{10} = -\frac{3 + 15 + 8}{10} = -\frac{26}{10} \]

Finally, we can simplify \(-\frac{26}{10}\):

\[ -\frac{26}{10} = -\frac{13}{5} \]

Thus, the final result is:

\[ -\frac{13}{5} \]