1 5/6+2/7
2. 8/9-5/12
3. 2m/3-4n/5
2007-11-26 07:52:20 · 3 answers · asked by lisa g 1 in Science & Mathematics ➔ Mathematics
when adding fractions, you need to first get common denominators. You do so by multiplying one or all fractions by 1 in the form of a fraction (i.e. 5/5, 3/3, 900/900, whatever/whatever)
1 5/6+2/7
(5/6)(7/7)+(2/7)(6/6)
35/42 + 12/42
47/42 is your answer
2. 8/9-5/12
(8/9)(4/4)-(5/12)(3/3)
32/36 - 15/36
17/36
3. 2m/3-4n/5
(2m/3)(5/5) - (4n/5)(3/3)
10m/15 - 12n/15
(10m-12n)/15
2007-11-26 07:59:18 · answer #1 · answered by Bollywood Masti 4 · 0⤊ 0⤋
they need common denominators.
1. 5/6 = 35/42 and 2/7 = 12/42, so then you add 12 and 35 and get 47/42 or 1.119.
2. 8/9 = 32/36 and 5/12 = 15/36, so then you subtract them and get 17/36.
3. common denominator of 15.
2m/3 = 10m/15 and 4n/5 = 12n/15. so the answer is just
10m-12n/15.
2007-11-26 16:02:13 · answer #2 · answered by ally 1 · 0⤊ 0⤋
they are just looking for you to use common denominators.
1.LCM of 6 and 7 is 42
5/6 = 35/42
2/7 = 12/42
35/42 + 12/42 = 47/42
2.LCM of 9 and 12 is 36
8/9 = 32/36
5/12 = 15/36
32/36 - 15/36 = 17/36
3.LCM of 3 and 5 is 15
2m/3 = 10m/15
4n/5 = 12n/15
10m/15 -12n/15 = (10m-12n)/15
2007-11-26 15:59:01 · answer #3 · answered by lhvinny 7 · 0⤊ 0⤋