5 replies to this topic

[Leaiku]

I'm having trouble with some maths at the moment, and I can't find a decent explanation anywhere for it that I understand so I thought I'd come to you guys ;u;
It's very simple (too most people anyway, not me) basically its just mulitplying negitive numbers/dividing with them. I don't get it AT ALL.
For eg. -8 x 7 =?? I don't know what to do/ how to do it. I know two negitives make a postive, so I can do stuff like -8 x -7 ok but not if theres only one negitive.
Same with dividing, apart from the fact that I don't know how to divide even if theres two negitives.
Please could someone explain to me? :c Sorry for asking for such simple things, I really suck at maths...

[Shirou_PL]

Its very simple. Here is explanation:
if you have two minus value is plus value so:

-8 x 7 is like 8 x 7 so its 56, but you have one minus so its -56.

Its the same with dividing too for example:

-36 : -9 is like 36 : 9 so its 4, then you have two minuses. so your not changing a sign of value.

I hope you will get it

[Leaiku]

Ohhh I get it now!
Yeah it is simple now that you've explained it like that and I get it c:
Thank you so much, now I can finally do my homework XDD;

[finn523]

Count the number of negative numbers being divided and multiplied. If that number is even (2,4,6 etc) than the answer is positive. If that number is odd(1,3,5,7,etc) the answer is negative.

IE:
1 * 2 * -3 = -6 There is 1 negative number in there, which is an odd number.
-1 * 2 * -3 = 6 There is 2 negative numbers in there, which is an even number.

1 * 2 * 3 / -1 = -6 Still 1 negative number. Division and multiplication do not make a difference here.

This trick DOES NOT HOLD if you have addition and subtraction running around.

[Shirou_PL]

finn523, on 19 September 2011 - 06:45 PM, said:

Count the number of negative numbers being divided and multiplied. If that number is even (2,4,6 etc) than the answer is positive. If that number is odd(1,3,5,7,etc) the answer is negative.

IE:
1 * 2 * -3 = -6 There is 1 negative number in there, which is an odd number.
-1 * 2 * -3 = 6 There is 2 negative numbers in there, which is an even number.

1 * 2 * 3 / -1 = -6 Still 1 negative number. Division and multiplication do not make a difference here.

This trick DOES NOT HOLD if you have addition and subtraction running around.

it actually do but its needed to remember of prority of multiply and divide over adding and subtraction

[Leaiku]

finn523, on 19 September 2011 - 06:45 PM, said:

Count the number of negative numbers being divided and multiplied. If that number is even (2,4,6 etc) than the answer is positive. If that number is odd(1,3,5,7,etc) the answer is negative.

IE:
1 * 2 * -3 = -6 There is 1 negative number in there, which is an odd number.
-1 * 2 * -3 = 6 There is 2 negative numbers in there, which is an even number.

1 * 2 * 3 / -1 = -6 Still 1 negative number. Division and multiplication do not make a difference here.

This trick DOES NOT HOLD if you have addition and subtraction running around.

Ohh thats a good trick I'll try that out! c:
Thank you~ ^^