81×(⅓)⁴-0,05×(-10)²

Let's solve the expression step by step.

The expression is:

\[ 81 \times \left(\frac{1}{3}\right)^4 - 0.05 \times (-10)^2 \]

1. Calculate \(\left(\frac{1}{3}\right)^4\): \[ \left(\frac{1}{3}\right)^4 = \frac{1^4}{3^4} = \frac{1}{81} \]

2. Now substitute this back into the expression: \[ 81 \times \frac{1}{81} - 0.05 \times (-10)^2 \]

3. Calculate \(81 \times \frac{1}{81}\): \[ 81 \times \frac{1}{81} = 1 \]

4. Next, calculate \((-10)^2\): \[ (-10)^2 = 100 \]

5. Now substitute this result back into the expression: \[ 1 - 0.05 \times 100 \]

6. Calculate \(0.05 \times 100\): \[ 0.05 \times 100 = 5 \]

7. Finally, subtract: \[ 1 - 5 = -4 \]

The final result is:

\[ \boxed{-4} \]