Basic Math
posted by Walter on .
I need help adding fractions with different denominators.
Here is the problem...
1  1/2 + 1/3  1/4 + 1/5  1/6
I can see that the demoninators increase. Since they are both addition and subtraction, how do I do this problem?
Thanks, Walter, New York.

1  1/2 + 1/3  1/4 + 1/5  1/6
You need to find the common denominator  the smallest number divisible by each of the denominators.
One way to do that is to find the multiples of the largest.
6, 12, 18, 24, 30, 36, 42, 48, 54, 60
Ahh  the common denominator is 60.
1/2 = 60/2 = 30/60
1/3 = 60/3 = 20/60
That should give you a good start. 
Okay, Now that the common demoninator is 60, I now multiply. But where do I start? for example, I just leave the 1 alone because its a whole number. So now I multiply the 1/2 to 1 * 30 = 30 and 2 * 30 = 60 Do I do the same for the 1/3 and so on?

1/2 = 30/60
1/3 = 20/60
What do you think 1/4 equals? 
1/4 = 15/60
1/5 = 12/60
What do you think? 
solve 5/30+3/40+1/8

what is 5/30 + 3/40 + 1/8