2007-02-14 01:48:36 · 17 answers · asked by dallen3330 1 in Science & Mathematics ➔ Mathematics
- 3/4 -(- 4/8) =
- 3/4 + 4/8
- 24/56 + 28/56 =
4/ 56=
1/14
- - - - - - - - -s-
2007-02-14 02:04:01 · answer #1 · answered by SAMUEL D 7 · 1⤊ 0⤋
In addition or subtraction with rational numbers ( fractions ), you need a common denominator. That would be the least common multiple for 7 and 8 in this problem. The LCD is going to be 56. So now rewrite the two fractions using the same denominator in both. ? / 56 and ?? / 56. In order to find the numerators, you take the given denominator and see how many times it will divide into the LCD, That answer is then multiplied times the numerator. Doing this would give :
- 24 / 56 - ( - 28 / 56 )
Now that the denominators are the same, you can do the subtraction problem. All of the work is done in the numerator and the LCD stays the same.
-24 - (-28) = -24 + 28
that gives 4 for the numerator.
the answer would be 4 / 56
Now simplify that or reduce the fraction by a factor of 4.
1/14 should be the answer.
Therefore:
-3/7 - (-4/8) = 1 / 14
There are some other ways to get the same answer, but this should work for all rational numbers.
2007-02-14 02:03:42 · answer #2 · answered by Ray 5 · 1⤊ 0⤋
Along with all the answers, just remember this (besides a common denominator):
Whenever you have to multiply a negative by a negative, you always get a positive.
So -3/7 -(-4/8) is like saying -3/7 + 4/8 because you distributing the negative sign into the number.
2007-02-14 01:59:32 · answer #3 · answered by Anonymous · 1⤊ 0⤋
You need a common denominator
-3/7 - (-4/8)
-24/56 + 28/56
4/56 = 1/14
2007-02-14 01:56:31 · answer #4 · answered by leo 6 · 1⤊ 0⤋
-(3/7) -(-(4/8))
two minus signs make a plus!
-(3/7)+(4/8)
make like denominators ....
((-3*8)/(7*8)) + ((4*7)/(8*7))
(-24/56) + (28/56)
-24+28=4
**with addition and subtraction the denominators don't get involved as long as you have found the common denominator**
Thus your answer is 4/56 now simplify to get 1/14
Hope that helped!
2007-02-14 03:03:59 · answer #5 · answered by Je 1 · 1⤊ 0⤋
-3/7-(-4/8)=
-3/7+4/8=
take 56 as LCD
-24/56+28/56=
4/56=1/14
2007-02-14 02:04:35 · answer #6 · answered by Dave aka Spider Monkey 7 · 1⤊ 0⤋
-3/7 - (-4/8) = -3/7 + 4/8 = -3/7 + 1/2 = -6/14 + 7/14 = 1/14
That's the really long version of the answer.
2007-02-14 01:55:48 · answer #7 · answered by Maeroc 2 · 1⤊ 0⤋
= -3/7 -(-4/8)
= -3/7 + 4/8
= -3/7 +1/2
= 1/2 - 3/7
By taking LCM
= (7 - 6)/14
= 1/14 (ANS)
2007-02-14 02:04:42 · answer #8 · answered by saqibzaheer77 1 · 1⤊ 0⤋
omg...what grade are u in that u can't do that? i learned that in 7th.
Well first of all get rid of the negative signs cause they cancel eachother out so your answer will be positive. Then you must find the common denominator between 8 and 7 which is ______. so 3/7 turnes into ______ cause whatever u do to the top u must to do the bottom. Then 4/8 becomes ______. Then reduce if needed after answering.
Those are the steps..not u figure it out.
2007-02-14 01:59:46 · answer #9 · answered by Got_a_question? 4 · 1⤊ 0⤋
1/14
2007-02-14 01:56:12 · answer #10 · answered by MF 2 · 1⤊ 0⤋