Q&A #770

Teachers' Lounge Discussion: least common multiple (LCM)

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From: Loyd

To: Teacher2Teacher Public Discussion
Date: 2011083111:52:12
Subject: Least Common Multiple

Just adding a note to what Gail calls skip counting.  

I have taught in several learning centers and also in literacy council
classes.  I have always used this method for teaching LCM.  

For example to find the LCM of 7 and 8, you can count as follows:
7, 14, 21, 28, 35, 42, 49, 56 
8, 16, 24, 32, 40, 48, 56 

We got a match with 56, so that is the Least Common Multiple. 

This is also good practice for learning multiplication facts.  I have
ran across several students (including adult students) who still
didn't know multiplication facts.  So, for them it might be good

I am not suggesting you use a calculator, but some calculators will do
skip counting by entering 0 and then enter + 5 for example and then
repeatedly pushing =.  Some calculators won't do this, such as the
CASIO fx-260 which is  approved for GED tests .  But I have one that
will skip count even if you are skipping in binary, octal, hexadecimal
or decimal.  That calculator is the LeWorld 250.  For example if you
want to skip count by 5's using binary you would change to Binary and
enter 0+101 and repeatedly press = and  it will count by 5's in
binary.  Then when you press 2nd F followed by DEC it converts to

Maybe not especially good for the entire class but maybe it would be
good for one of those bored students that is way ahead of the rest of
the class. 

The best way to learn anything is to enjoy learning it. Some students
will enjoy it and others won't.  

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