Math Lesson 3
Fractions, Decimals II

Instruction 3-5

USING LCM TO SOLVE FRACTION PROBLEMS 

http://www.math.com/school/subject1/lessons/S1U3L3GL.html

http://mathforum.org/library/drmath/sets/select/dm_lcd.html

http://www.helpwithfractions.com/greatest-common-factor.html

http://fclass.vaniercollege.qc.ca/web/mathematics/real/Calculators/GcdLcm_Calc_1.htm

http://www.helpwithfractions.com/prime-numbers.html