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Factors and Multiples Goal for your child: Your child will need to know the difference between a factor and a multiple in order to apply it to future math problems like know a prime or composite number and operating with fractions. Vocabulary: Factors: numbers that multiply together to give you a multiple. Example: Factors of 18 are 9x2. 6x3. 18x1 (1,2,3,6,9,18) Multiples: numbers that are the answer when you multiply two factors together. Example: Multiples of 5: 5,10,15,20,25,30,35,40,45 etc. Factor x Factor = Multiple Prime Number: A number that only has 1 and itself as its factors. Composite Number: A number that has more than 2 factors. Why does my child need to know these things? Your child will sometimes need to list the factors of a number when they need to find out if a number is prime or composite OR when they need to simplify a fraction (see When to Apply Factors section). Your child will need to list the multiples of a number when needing to make denominators the same in 2 fractions needing to be added or subtracted (see When to Apply Multiples section). Prime Factorization “Cherry Tree” Used when needing to know if a number is prime or composite 51 17 17 3 17 1 Prime Factorization: 17x3 Prime Factorization: 17x1 Composite Number Prime Number When to Apply Factors AKA—find the GCF of a fraction and simplify. GCF Checklist: Factors of 9: List the factors of the top and bottom numbers. Circle the matching factors of the top and bottom numbers Use the greatest circled number and divide into both the top and bottom number of the fraction. 9 x 1, 3 x 3 Factors of 12: 12 x 1, 3 x 4, 6 x 2 9 ÷ 3= 3 12 ÷ 3 = 4 When to Apply Multiples LCM Checklist: List the multiples of just the bottom numbers (denominators). Circle the matching multiples of the top and bottom numbers Use the smallest circled number as your new denominator (bottom number). Create a multiplication fact and multiply by the boxed number to create your new fractions with matching denominators. Add your top numbers together and keep your denominator the same to get your answer. 3 x 2= Multiples of 4: 4, 8, 12, 16, 20, 24 c + Multiples of 8: 8, 16, 24, 32, 40, 48 c c 4 x 2= 5 x 1= 8 x 1= 6 8 5 8 11 8 Parent Cheat Sheets—KASH—2012