3 1/8+2 1/12-1/3/7,3-0,4*8,5

To solve the expression \(3 \frac{1}{8} + 2 \frac{1}{12} - \frac{1}{3}/7 + 3 - 0.4 \times 8.5\), we can break it down step by step.

1. Convert mixed numbers to improper fractions:

   • \(3 \frac{1}{8} = \frac{25}{8}\)
   • \(2 \frac{1}{12} = \frac{25}{12}\)

2. Convert the fractional division:

   • \(\frac{1}{3} / 7 = \frac{1}{3} \times \frac{1}{7} = \frac{1}{21}\)

3. Work with the decimal multiplication:

   • \(0.4 \times 8.5 = 3.4\)

Now let's substitute these values back into the expression:

\[ \frac{25}{8} + \frac{25}{12} - \frac{1}{21} + 3 - 3.4 \]

Next, we'll convert the constants and fractions to a common denominator to simplify the addition and subtraction.

4. Convert constants to fractions:

   • \(3 = \frac{24}{8}\)
   • \(3.4 = \frac{34}{10} = \frac{17}{5}\) (but for consistency, let's keep it as \(3.4\) for now)

5. Find the common denominator for the fractions (24 is a good candidate since it is a multiple of 8, 12, and 21):

   • Convert \(\frac{25}{8}\) into 24ths: \(\frac{25 \times 3}{8 \times 3} = \frac{75}{24}\)
   • Convert \(\frac{25}{12}\) into 24ths: \(\frac{25 \times 2}{12 \times 2} = \frac{50}{24}\)
   • Convert \(\frac{1}{21}\) to 24ths: \(\frac{1 \times 24/21}{21 \times 24/21} = \frac{24}{441} = \frac{8}{147}\) (however, once simplified, we will do this last)

Putting it all together:

• \(\frac{75}{24} + \frac{50}{24} - \frac{8}{147} + \frac{24}{8} - 3.4\)

Let's try to compute:

First combine fractions: \[ \frac{75 + 50}{24} - \frac{1}{21} + \frac{3.4 - 3.4}{1} \] \[ \frac{125}{24} - \frac{8}{147} + \left(\frac{24}{24} - 3.4\right) \]

To subtract \(3.4\), you'll just need to treat its fractional form for clean calculation.

Let’s combine all:

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