Notes 2.4 Number Patterns: Prime Factorization A prime number has exactly two factors: 1 and itself. Two is the only even prime number. A composite number has more than two factors. The number 1 is neither prime nor composite. Example: 81 = 3*3*3*3 or 3^4 You can write the prime factorization as the product of factors or exponentially. We will do the prime factorization by dividing by prime numbers.

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homework answers 7)1–neither, 2-prime, 3-prime, 4-composite, 5=prime, 6-composite, 7-prime, 8- composite, 9-composite, 10-composite, 11-prime, 12-composite, 13-prime, 14- composite, 15-composite, 16-composite, 17-prime, 18-composite, 19-prime, 20- composite, 21-composite, 22-composite, 23-prime, 24-composite, 25-composite 9)2 3 x7 11) 2 4 x3 2 13) 2 4 x3 2 x5 15) 2x3x5x7x11 17) ) 54 21) 90

23) 26; composite 32) B 33) D 34) C 35)mpa: Numerals are written as the product of their prime factors; 28, you need to know the symbol for 13. SR 1) 9x5, 45x1, 15x3 2)8x6, 12x4, 16x3, 24x2, 48x1 3)9x8, 12x6, 18x4, 24x3, 36x2, 72x1 4)10x8, 16x5, 20x4, 40x2, 80x1 5)27 6) 110 7) 57 8) 60 – x = 8; $52 9) E 10) G 11) C 12) B 13) F 14) D

15) 39; 78 16) 25; 22 17) 101; ) 48; 24 8)2 4 x3 10) 2x3x5 2 12) 2 5 x3x7 14)3x5x ) 66 18) 56 20) 84 22)11; prime 24) 41; prime 28) 35 29)36 30) 18 or 24 MCA 1)5x9(9+2)=55 2) 45-6x(2+3)=15 3) 36/(3+6)/2=2 4) (27-18)/(6-3)=3

5) 125 6) 64 7) 243 8) 64 9) C 10) A 11) D 12) B 13) 84x1, 42x2, 28x3, 21x4, 14x6, 12x7 14) ) ) ) ) false; 2 3 is the same as 2x2x2 or 8 19) true 20) false; the expression (6x8)- (6/2) is equal to ) true 22) Yes; three divides evenly into both the length and the width.