(3/8+(1/2)во 2-ой степени+1цел 1/4):5/3=1,667

Let’s solve the expression step by step.

The original expression is:

\[ \left(\frac{3}{8} + \left(\frac{1}{2}\right)^2 + 1 \frac{1}{4}\right) \div \frac{5}{3} \]

1. First, calculate \(\left(\frac{1}{2}\right)^2\): \[ \left(\frac{1}{2}\right)^2 = \frac{1}{4} \]

2. Now substitute back into the expression: \[ \frac{3}{8} + \frac{1}{4} + 1 \frac{1}{4} \]

3. Convert \(1 \frac{1}{4}\) to an improper fraction: \[ 1 \frac{1}{4} = \frac{5}{4} \]

4. Now the expression looks like: \[ \frac{3}{8} + \frac{1}{4} + \frac{5}{4} \]

5. Convert \(\frac{1}{4}\) to eighths to combine: \[ \frac{1}{4} = \frac{2}{8} \] \[ \frac{5}{4} = \frac{10}{8} \]

6. Now add everything together: \[ \frac{3}{8} + \frac{2}{8} + \frac{10}{8} = \frac{3 + 2 + 10}{8} = \frac{15}{8} \]

7. Now, substitute back into the division by \(\frac{5}{3}\): \[ \frac{15}{8} \div \frac{5}{3} = \frac{15}{8} \times \frac{3}{5} = \frac{15 \times 3}{8 \times 5} = \frac{45}{40} \]

8. Simplify \(\frac{45}{40}\): \[ \frac{45}{40} = \frac{9}{8} \]

9. Convert to decimal: \(\frac{9}{8} = 1.125\)

Thus, the final answer for the expression is:

\[ 1.125 \text{ (or } 1 \frac{1}{8} \text{ in mixed number form)} \]

It seems the earlier assertion that the expression equals \(1.667\) is incorrect. The correct result is 1.125.