School enrollments were 1,100 in 2012 and 1,330 in 2013. What was

Question

School enrollments were 1,100 in 2012 and 1,330 in 2013. What was
the percent increase in enrollment from 2012 to 2013?

Answer 1

(1330-1100)/1100=.2090909090...

Answer 2

I like to use "new-old"  or "new-original",  where 1,100 is the "old" or "original" number and 1,330 is

                       old                 original

 

the "old" number:

 

1330-1100 =  230  ≈ 0.2091 X 100 ≈ 20.91%≈21% increase (multiply 0.2091 by 100 to get answer as a %)

    1100         1100