please someone help me!!

tyu

my dad will kill me if i dont do these maths questions he left me to do
but see he exagerates...these questions are for maths masters im onloy 16
please i know the answer
but i just need to know how to get to the answer ,its adding fractions
{7/7 means 7 over 7}

7/25 + 8/105 + 9/21 + 11/50 + 1/63

the answer is 1/13/630

it would b a great help if anybody could help me out
thanks

fletch

Not gona answer it for you, just give you a hint....to add all those fractions....first you need to get them to a common base...to do so you need to find the LCM (lowest common multiple) and then right each fraction in terms of the LCM...
so for example
1/4 + 1/8
The LCM of 4 and 8 is 8 so now we write the sum as
2/8 + 1/8
giving an answer of
3/8
Hope this helps

Pigman II

I suppose I could do your homework for you, but first what is 1/13/630 supposed to mean?

tyu

yea i know that you have to do that thanks anyway
but see theres too much fractions...

Jeanious

the way id do it is take 7/25 and 11/50 separately (cos its easy to find the lcm)

then take 9/21 and 1/63 and do the same.

then youve only 3 fractions to get the lcm for (or two really cos one of them is a piece of pi$$)

fletch

7/25 + 8/105 + 9/21 + 11/50 + 1/63
LCM of 25, 105, 21,50 and 63 is 3150
7/25 = 882/3150 (882 = 3150 / 25 = 126 * 7)
8/105 = 240/3150 (240 = 3150 / 105 = 30 * 8)
9/21 = 1350/3150 (1350 = 3150 / 21 = 150 * 9)
11/50 = 693/3150 (693 = 3150 / 50 = 63 * 11)
1/63 = 50/3150 (50 =3150 / 63 = 50 * 1)

Adding them all
(882+240+1350+693+50)/3150 = 3215 / 3150 = 1/13/630

tyu

its not homework man, im on holidays im bein honest here my dad will kill me if i dont have these done before he gets home today

1/13/630 is

1 whole with 13 over 630

do you know what i mean now its the answer to the question i just need to know how to get to the answer
thanks

fletch

tyu wrote:

yea i know that you have to do that thanks anyway
but see theres too much fractions...

Theres not too many fractions....
1/13/630 means 1 and 13/630ths i.e 1.020634921

tyu

ok il try and see wat i can make out of that
thanks really
youve been a great help

fletch

You may need to explain to him how you found the LCM...pretty simple task too....check out this website for an explanation....

tyu

aw man thanks seriously
ive been lookin this up all day
thanks

tyu

oh yea one more question if you dont mind
why do i multiply the top numbers {7,8,9,11,1}
by the times it would take them to get to 3150
like wats the reason?
if you dont mind

Pigman II

Forget about the multiplying that you see written above as it'll just confuse you (what fletch wrote up there 'technically' isn't correct - even tho I know what he meant) ,

just look at this way and it might be clearer.............

7/25 = 882/3150
8/105 = 240/3150
9/21 = 1350/3150
11/50 = 693/3150
1/63 = 50/3150

fletch

Pigman II wrote:

Forget about the multiplying that you see written above as it'll just confuse you (what fletch wrote up there 'technically' isn't correct - even tho I know what he meant) ,

just look at this way and it might be clearer.............

7/25 = 882/3150
8/105 = 240/3150
9/21 = 1350/3150
11/50 = 693/3150
1/63 = 50/3150

Yes 'technically' now that I look at it, it wasn't correct, I was just trying to show him the steps in between to arrive at the appropriate fractions in each case.....edited it to make it clearer...anyways OP is sorted now

Tree

do they not teach LCM in primary school anymore? i remember doin it in busy at maths along with HCf and some other acronyms

tyu

yea i knew how to do that, just the question was tricky for me
im only 16