Hi, urm.. please help!?
2007-09-10 07:46:18 · 10 answers · asked by Anonymous in Education & Reference ➔ Homework Help
The thing with these fractions is that the numbers underneath are different. To do anything with them, you need to make them all the same.
If you think of 8ths, there will be 4 of them in 1/2.
This is the way you look at the other fractions - what number can have 5ths, 3rds and 8ths in?
The easiest way is to see if any fit into the others.
2 goes into 8, so will fit into any number with 8 in.
8, 3 and 5 will not fit into each other, so multiply them together, to get a number they will all go into.
8 x 5 = 40
40 x 3 = 120
now take each fraction and turn it into 120ths.
1/2 = 60/120 because 2 goes into 120, 60 times
1/8 = 15/120 because 8 goes into 120, 15 times
5/8 is 5 times bigger than 1/8 so
5/8 = (5 x 15)/120 = 75/120
this means the other fractions are
1/5 = 24/120 so 3/5 = 72/120
1/3 = 40/120
so altogether you get
60/120 + 75/120 + 72/120 - 40/120
just work out the top bit, because they are all over 120 now
60 + 75 + 72 - 40 = 167
so this is 167/120
167 is bigger than 120, so you get
120/120 + 47/120
this gives you 1 and 47/120 as the answer
It gets easier with practice!
2007-09-10 08:46:06 · answer #1 · answered by Borogrove 3 · 0⤊ 0⤋
1/2 + 5/8 +3/5 - 1/3 (bring every thing to a common denominator '120' in this case). The denominator can be found by multiplying the four denominators together - 2x8x5x3= 240. Then halving the number and checking the 4 denominators will divide into 240/2 = 120 without remainder.
60/120 + 75/120 + 72/120 - 40/120 (Add/subtract the numerators (top number) together and place over 120).
167/120 (Reduce this improper (top heavy) fraction to a mixed fraction by dividing through by 120).
1 & 47/120 - The answer.!!!!!
2007-09-10 08:00:42 · answer #2 · answered by lenpol7 7 · 0⤊ 0⤋
The Lowest Common Multiple is 120 so change them in to fractions over 120. You get
60/120 + 75/120 + 72/120 - 40/120
So you get 207/120 - 40/120
This is 167/120
2007-09-10 07:57:20 · answer #3 · answered by Emma C 4 · 0⤊ 0⤋
first you have to find the common deminator. you can do this in pieces:
(4/8 + 5/8) + 9/15 - 5/15
= 9/8 + 4/15
find common denominator again
15x8 = 120
135/120 + 32/120 = 167/120
or 1 + 47/120
2007-09-10 07:52:02 · answer #4 · answered by dan 4 · 0⤊ 0⤋
1/2 + 5/8+ 3/5 - 1/3
or
4/8 + 5/8 + 9/15 - 5/15
then
9/8 + 4/15
translates to
135/120 + 32/120
which equals
167/120
or 1 and 47/120
2007-09-10 07:57:50 · answer #5 · answered by honesty.speaks 2 · 0⤊ 0⤋
This is not a series. The term 1/3 is LESS than the previous term, all the others are more than the previous term. I think that the series you mean should be 1/2 . . 3/4 . . 5/8 . . 7/16 . . (2n - 1)/2^n
2016-05-21 05:55:53 · answer #6 · answered by mathilda 3 · 0⤊ 0⤋
Find the least common denominator (smallest number that each of the deniminators go into). Then create similar fractions and solve the problem.
2007-09-10 07:50:35 · answer #7 · answered by stylestj 2 · 2⤊ 0⤋
What do you think the common denominator is?.....How 'bout 120?....so you have 60/120 + 75/120 + 72/120 - 40/120 = ?
2007-09-10 07:54:32 · answer #8 · answered by JoiseyFlyboy 2 · 0⤊ 2⤋
Don't let things like this bother you. Use a scientific calculator or something. Trust me, there will be no real life situation in which you encounter a problem like this. Answering questions like this one has no educational value whatsoever. In fact, most stuff to do with fractions has no educational value, seeing as decimals are far more logical and easier to work with.
Regards,
Rob.
2007-09-10 07:52:48 · answer #9 · answered by Robert W 3 · 2⤊ 2⤋
find the lowest common denominator first. It would be 40 then take it from there.
2007-09-10 07:52:59 · answer #10 · answered by D B 6 · 0⤊ 1⤋