Question

medal for answer
Solve two-fifths plus one-ninth. Then use estimation to check for reasonableness. Show your work.

Answer 1

I suggest for you to use benchmark estimates like 0, 1/2, or 1. Those are the most common types of estimations.

Answer 2

To add 2/5 and 1/9, first you need to find a common denominator. The smallest common denominator for 5 and 9 is 45. The equivalent fraction for 2/5 is 18/45. The equivalent fraction for 1/9 is 5/45. So the re-stated problem is 18/45 plus 5/45.

18/45 + 5/45 = 23/45.

As far as using estimation to check for reasonableness... 2/5 as a decimal is .4, which as a percent is 40%. 1/9 is very close to 1/10, which is 10%. If you added 40% and 10% you would get 50%. Now if you look at the fraction 23/45, it is almost exactly .5 which is 50%. Exactly half of 45 is 22.5, so 23 is very close to 50%. So 23/45 is very reasonable.

I hope all the steps were clear.

Answer 3

So two fifths rounds off to 0 and one ninth rounds off to 0. But to make sure add the two fractions together normally.