SOLUTION: Hi, I'm trying to help my son with this problem. My answer was 23/30 is that correct? Simplify: 2/3 +3/10 -2/5 2/3 + 3/10 = 11/30 then that minus 2/5? When I did it on an on

Algebra ->  Average -> SOLUTION: Hi, I'm trying to help my son with this problem. My answer was 23/30 is that correct? Simplify: 2/3 +3/10 -2/5 2/3 + 3/10 = 11/30 then that minus 2/5? When I did it on an on      Log On


   



Question 258846: Hi, I'm trying to help my son with this problem. My answer was 23/30 is that correct?
Simplify: 2/3 +3/10 -2/5
2/3 + 3/10 = 11/30 then that minus 2/5? When I did it on an online math calculator, it said the answer is 17/30. I don't understand how that can be?
Thanks for your help! :)

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Whenever you have fractions, you need a common denominator.
In this case 30 will work. It's also the least common denominator.
Convert each to a fraction with a denominator of 30.
%282%2F3%29%2810%2F10%29=20%2F30
%283%2F10%29%283%2F3%29=9%2F30
%282%2F5%29%286%2F6%29=12%2F30
So then
%282%2F3%29%2B%283%2F10%29-%282%2F5%29=20%2F30%2B9%2F30-12%2F30
%282%2F3%29%2B%283%2F10%29-%282%2F5%29=%2820%2B9-12%29%2F30
%282%2F3%29%2B%283%2F10%29-%282%2F5%29=17%2F30