Atown had about 2120 acres of pine trees 40 years ago. only about 13% of the pine trees remain. how many acres of pine trees remain?

This one is easier than it might look.

You need to find 13% of 2120. The easiest way is find 1% of 2120 and then mulitply that answer by 13.

1% is just moving the decimal point over by 100, so the 1% number is 21.2
Now we do 21.2 times 13, and get 275.6 (I used a calculator).

Just to double check that our answer is about right and we done anything really dumb, we look at the first number, and think to ourselves that 13 percent is close to 10 percent, and 10 percent of 2,120, is about 212, so that our answer is in the right area. Good.

Submit your final answer as 275.6.

Number 40 is a rational number glad i could