1. The problem asks to express 400% as a fraction and as a decimal. 2. Recall that percent means "per hundred," so 400% means 400 per 100. 3. To convert a percent to a fraction, write it as \frac{400}{100}. 4. Simplify the fraction by dividing numerator and denominator by their greatest common divisor, which is 100: $$\frac{\cancel{400}}{\cancel{100}} = \frac{4}{1} = 4$$ 5. So, 400% as a fraction is $4$ (or $\frac{4}{1}$). 6. To convert a percent to a decimal, divide by 100: $$400\% = \frac{400}{100} = 4.0$$ 7. Therefore, 400% expressed as a fraction is $4$ and as a decimal is $4.0$.