39. MULTIPLE CHOICEIn what order should you perform the operations in the expression 4 ×3 −12 ÷2 +5? (Section 1.3)A×, −, ÷, +B×, ÷, −, +C×, ÷, +, −D×,
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Room 1Room 2adjoining wall4

36
Chapter 1
Numerical Expressions and Factors
How can you find the least common multiple
of two numbers?
Least Common Multiple
1.6
Work with a partner. Using the first several multiples of each number, copy and complete the Venn diagram. Identify any common multiplesof the two numbers.a. 8 and 12Multiplesof 8Multiplesof 12b. 4 and 14Multiplesof 4Multiplesof 14c. 10 and 15Multiplesof 10Multiplesof 15d. 20 and 35Multiplesof 20Multiplesof 35e. Look at the Venn diagrams in parts (a)–(d). Explain how to identify the least common multiple of each pair of numbers. Then circle it in each diagram.Identifying Common MultiplesCommon MultiplesIn this lesson, you will●use diagrams to identify common multiples.●find least common multiples.
ACTIVITY:
1

Section 1.6
Least Common Multiple
37
Work with a partner. a. Write the prime factorizations of 8 and 12. Use the results to complete the Venn diagram.b. Repeat part (a) for the remaining number pairs in Activity 1.c. STRUCTURECompare the numbers from each section of the Venn diagrams to your results in Activity 1. What conjecture can you make about the relationship between these numbers and your results in Activity 1?ACTIVITY: Interpreting a Venn Diagram of Prime Factors3. IN YOUR OWN WORDSHow can you find the least common multiple of two numbers? Give examples to support your explanation.
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4. The Venn diagram shows the prime factors of two numbers.232235Use the diagram to do the following tasks.a. Identify the two numbers.b. Find the greatest common factor.c. Find the least common multiple.5. A student writes the prime factorizations of 8 and 12 in a table as shown. She claims she can use the table to find the greatest common factor and the least common multiple of 8 and 12. How is this possible?8 =12 =2232226. Can you think of another way to find the least common multiple of two or more numbers? Explain.Use what you learned about least common multiples to complete Exercises 3–5 on page 40.
Primefactorsof 8Primefactorsof 12
Construct ArgumentsHow can you use diagrams to support your explanation?
Math
Practice