PRIME FACTORIZATION AND GREATEST COMMON FACTOR GCF PREALGEBRA

PRIME FACTORIZATION AND GREATEST COMMON FACTOR (GCF) PRE-ALGEBRA MR. RIVERA

WARM UP FACTOR USING A FACTOR TREE 60 123 x³ 90 y²

OBJECTIVES • To learn how to find the prime factors of a number using a factor tree • To learn how to find the GCF of two numbers

PRIME NUMBERS • A number that is bigger than 1 • Only has two factors • 1 and itself • Example: 7 --- 1, 7 PRIME NUMBERS UP TO 15 2, 3, 5, 7, 11, 13

COMPOSITE NUMBERS • Positive number bigger than 1 • Has more than two factors • Example: 4, 6, 8, 9, 10

PRIME FACTOR TREE 1) The number you start with is the top of the tree 2) We factor the top of the tree by finding two numbers that multiply to produce top number 3) If factors are not prime, we factor again, until all numbers are prime Every “branch” is a new level of factors 36 = 3² · 2²

PRIME OR COMPOSITE? IF COMPOSITE, MAKE A FACTOR TREE, WRITE THE PRIME FACTORS, THEN WRITE IN EXPONENTIAL NOTATION 11 18 28 a² 30 b²

MAKE A FACTOR TREE FOR THE FOLLOWING NUMBERS 225 30

GREATEST COMMON FACTOR • Factors that are the same for two or more numbers are common factors • Multiply common factors to find the GREATEST COMMON FACTOR • IF THERE IS ONLY ONE COMMON FACTOR • THAT’S THE GCF

FIND THE GCF 6, 15 45, 90 36, 24

CLASSWORK • Page 183 Check Understanding 11 -15 Practice Problem Solving 29 -33 41 -45 HOMEWORK IF YOU DON’T FINISH!! Videos for extra help • https: //www. youtube. com/watch? v=u. E 9 O 8 N 5 JYB 4 • https: //www. youtube. com/watch? v=6 s. Lyr 2 X 3 Y 94