What is 20 percent of 644000 - step by step solution

To get the solution, we are looking for, we need to point out what we know.

1. We assume, that the number 644000 is 100% - because it's the output value of the task.
2. We assume, that x is the value we are looking for.
3. If 644000 is 100%, so we can write it down as 644000=100%.
4. We know, that x is 20% of the output value, so we can write it down as x=20%.
5. Now we have two simple equations:
1) 644000=100%
2) x=20%
where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
644000/x=100%/20%
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for what is 20% of 644000

644000/x=100/20
(644000/x)*x=(100/20)*x       - we multiply both sides of the equation by x
644000=5*x       - we divide both sides of the equation by (5) to get x
644000/5=x
128800=x
x=128800

now we have:
20% of 644000=128800