Increase- to be more significant in value, to be of more worth, to have a larger quantity.
Basically, if I said I added 2 to 5, that would be an increase.
2+5=7 7 is bigger than 5.
If I subtracted 2 from 5, that would make a decrease in value.
5-2=3 3 is smaller than 5.
I hope this helps!
~kaikers