Answer: 300 percent
Step-by-step explanation:
Where: 15 is the old value and 60 is the new value. In this case we have a positive change (increase) of 300 percent because the new value is greater than the old value.
Usually its easier to subtract numbers written vertically because of the sheer fact that you're just taking away instead of adding on. If you have basic idea about adding then you should understand subtracting easier. But, because most schools teach adding first its easier for some.