Expert: John Zalewski - 2/7/2012

Question
find each sum or difference. write the anwser in simplest form 1... one and three tenths + three and two fifths

Answer
Hello, David.

1 3/10 + 3 2/5


The first step in this problem is to convert each mixed number into an improper fraction. To do this, first multiply each denominator by its respective whole number, then add that total to the numerator. Keep the denominator the same for the fraction.

So, for 1 3/10, first multiply the denominator (10) by the whole number (1), giving you 10. Next, add that total to the numerator (3), giving you 13. The denominator stays the same, so the improper fraction will be 13/10.

For 3 2/5, follow the same steps. Multiply the denominator (5) with the whole number (3), giving you 15, and add that to the numerator (2), giving you 17. The denominator stays the same, so your new fraction is 17/5.

Now, you can add, since you have two fractions: 13/10 + 17/5.

To add these fractions, you need to have a lowest common denominator. The lowest common denominator is the lowest number in which both current denominators will evenly divide into. So, for our denominators (10 and 5), the lowest common denominator is 10, since 10 is the lowest number both 5 and 10 evenly divide into.

Each numerator will change based on what factor the old denominator changed. For 17/5, the 5 changes to the lowest denominator 10 (a factor of 2), so the numerator changes to 34 (17x2 = 34).

For 13/10, the denominator remains the same, because it's already the lowest common denominator, and so the numerator also stays the same.

13/10 + 34/10

Now we can add, since we have identical denominators. Add the numerators together (13+34 = 47), and leave the denominator the same, giving you an answer of 47/10.

Answer: 47/10

Hope this helps.

Regards,
John