Page 17 - 新思维数学学生用书7 样章

1 Integers

4 Find the LCM of 8 and 12.

5 Find the LCM of 10 and 15.
6 Find the LCM of 7 and 8.

Think like a mathematician

7 Look at this statement: If A and B are two whole numbers, then A × B is a
common multiple of A and B.
a Show that the statement is true when A = 4 and B = 7.
b Show that the statement is true when A = 6 and B = 5.
c Is the statement always true? Give evidence to justify your answer.

d Look at this statement: If A and B are two whole numbers, then A × B is the
lowest common multiple of A and B.
Is this statement true? Give evidence to justify your answer.

8 Find the LCM of 3, 4 and 6.
9 Find the LCM of 18, 9 and 4.
10 21 is the LCM of two numbers. What are the numbers?

11 30 is the LCM of two numbers. What are the numbers?

How did you answer questions 10 and 11? If you were asked another question
similar to questions 10 and 11, would you do it the same way?

Summary checklist

I can find the lowest common multiple of two numbers by listing the multiples
of each number.

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