Friday
October 31, 2014

Homework Help: math

Posted by missy on Wednesday, April 18, 2007 at 9:16pm.

I don not understand how to do least common mutiples.
Can I please get some help.

I need to find the least common multiple of 420 and 196.

there is a real neat way to do this which works for the LCM of any number of numerals.

420 196
-------| divide each number by a common factor
105 49 | 4
15...7.} 7

there are no more common factors
so the LCM is the multiplation of the numbers on the far right as well as the last row
so LCM = 4 x 7 x 15 x 7 2940

if you had more than 3 numbers to start with there was a common factor for only some of them, take it out until there is no common factor for any

e.g.

400 250 230

200 125 215 | 2
40..25 43...| 5
8....5 43...| 5

so LCM = 2x5x5x8x5x43

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

lcm - find the least common mutlipe of 420 196 Break down each number into prime...
MATH - HOW DO LEAST COMMON MULTIPLES WORK. IT SAYS THERE IS A PROBLEM TO SOLVE ...
algebra - how would i find least common multiple of 20, 50 and 3 ? okay well you...
Math - I am trying to decide between 2 answers on a vocabulray question. The ...
math - 1. What is the greatest common factor of: 2x2x5x7x7 2x5x5x7x7 a. 2x5 b. ...
Math - List the common multiples from 1 to 100 for each pair of numbers. Then ...
Elementary Math - A student asks about the relation between least common ...
Algebra II - Our current assignment is to find the LCM, Least Common Multiple of...
Math - I still do not understand fractions?????? 2/3 + 1/3 + 5/6 = divide all of...
algebra ! - i need hepl on adding and subtacting rational numbers like -7over12+...

Search
Members