lcm of 280 and 784?

Answer 1

You can easily find the lcm of two numbers by finding the gcd (which is a little easier to find) and then:

lcm(m,n) = (mn)/(gcd(m,n))

So to find the gcd, you can list all the factors or you can use the Euclidean Algorithm (I suggest you look up and use the latter, since it's EXTREMELY fast and easy to use).

784 = 2(280) + 224
280 = 1(224) + 56
224 = 4(56) + 0

So using the Euclidean Algorithm (that's what I just did, and that's how fast it is, compared to listing the factors), we see that gcd(280,784) = 56.

so lcm = ((280)(784))/(56) = 3920

So the least common multiple of 280 and 784 is 3920.

Hope this helps!!

Answer 2

280 = 2*2*2*7*5
784 = 2*2*2*2*7*7
so LCM= higest powers(2^4*7^2*5)

Answer 3

its easy to find using thos formula
l.c.m*g.c.d=n1*n2
gcd of two numbers =56
56*i.c.m =280*784
L.C.M=3920

Answer 4

Why don't you practise a bit of math? It will help you during exams- you know. You can't have everything answered by others. Anyway- since so many have already answered this, I will not bother doing so again.

Answer 5

Go read http://amby.com/educate/math/2-1_LCM.html
and then learn to factor.

It's too late for me to type all that stuff ☺


Doug

Answer 6

i could easily figure that out witha piece of paper and a pencil

Answer 7

3920-->
280=2*2*2*5*7
784=2*2*2*2*7*7
LCM=2*2*2*2*5*7*7=3920

Answer 8

3920

Answer 9

3,920.