Chap 2: Real Numbers - Investigative Activity (II) Product of Integers

In this investigative activity, you are going to multiply integers of different combinations:

• positive and positive integers
  
• positive and negative integers
• negative and negative integers

Observe patterns amongst the answers generated.
Draw up a 'rule' that would guide us when we multiply integers (especially when it involves negative integers).

Vocabulary List: Numerical Part. Sign. Positive. Negative. Product.

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You are going to work in pairs or threes.

1. One of you will download the file "Chapter 2 Investigative Activity - Addition and Product.numbers" (from GoogleSite: 01 Mathematics). Another will display the blog post so that you could enter your discussion into the Comments.




2. Refer to the worksheet "Product of Numbers":

• (a) Enter formula to find the value of "a x b" of the first set of numbers (i.e. (-4) x (-4)).

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• Press ENTER and the spreadsheet will compute the value automatically.
• (b) We are going to tell the spreadsheet to use the row of numbers in Row 2 and Column B for computation.
• At the formula bar, click at C2 and select (C$2) absolute row. The spreadsheet will use the numbers in Row 2 for calculation.

• At the formula bar, click at B3 and select ($B3) absolute column. The spreadsheet will use the numbers in Column B for calculation.

• (c) To copy the formula, select cell B3, place the cursor at the bottom right corner. It will turn to a cross-hair. Now drag it to cover the entire area to be computed.

3. Discuss the patterns you observe between the product of integers:

• (a) What happens when a positive integer x a negative integer (given that the positive number has a greater numerical value)?
• (b) What happens when a positive integer x a negative integer (given that the positive number has a smaller numerical value)?
• (c) What happens when a negative integer x a negative integer? How similar or different it is when compared the product two positive numbers?

4. Pen the observations down in the Comments. Suggest a rule that would help one when adding two numbers.

5. Sign off the Comments with the name(s) of both of you.

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