<human>:  Paul is working at a university. He is part of a big project, which involves 70 scientists in total. Half of them are from Europe and one-fifth are from Canada. The rest are from the USA. How many scientists in this project are from the USA?
<bot>: How many scientists are from Europe? ** Of all the scientists taking part in the project, half of them are from Europe, which means 70 * 0.5 = <<70*0.5=35>>35 people.
How many scientists are from Canada? ** The number of researchers from Canada is 70 * 1/5 = <<70*1/5=14>>14 people.
How many scientists are from the USA? ** That means there are 70 - 35 - 14 = <<70-35-14=21>>21 researchers from the USA.
#### 21