sub. and add. fractions

[tnt3]

Hello.
I need help! I cant remember how to add or subtract fractions.I have been out of school to long i guess. My 7th grader
needs my help, and i need yours Can you please tell me step by step how to figure out these problems. For example

4 2/3 6 or 2/3 +5/8 +1/6= 7 3/5 +4 1/2 + 5 3/20=
- 3 1/4 - 2 1/2
-------- ---------- Thanks

 

[jayb]

2/3 + 5/8 + 1/6
find the number that's divisible by all the denominators
24 is divisible by 3,8 and 6
3*8=24, 8*3=24,6*4=24
now consider the numerators: Do 2*8, 5*3, 1*4
that gives 35.
So the answer is 35/24.


Follow the same procedure for others.

 

[mmm4444bot]

CLICK HERE to go to a web site with some basic lessons on fractions. (Adding fractions with different denominators is explained in lesson 12, but your 7th-grader might benefit from working through the entire page in order.)

Feel free to come back here and ask specific questions about anything you see there.

Cheers ~ Mark

 

[DrMike]

Or, for some worked examples, see here or here.