Answer:
320
Explanation:
Well, you could use a calculator and multiply 400 by 0.8 which is 320.
This is because when finding a percent of something percent means per/hundred. Basically meaning 1% is 1/100, and so on. 1/100 as a decimal is 0.01. By this idea, we can say that 80% would just be 80 times bigger than 1%. You can then say that 80% is just 0.8. So, take your whole number that you are trying to find the percent for and simply multiple it by 0.8.