3.2+Subtracting+on+a+Number+Line

10/4/09**
 * S.T.

=Big Idea: Negative numbers help us to model many real world situations.= = Essential Question: How do I find the difference between integers? =

=3.2 & Follow-up= = = 1) +7-+9= -2 2) -7-+9= -16 3) +7- -9= 16 4) -7- -9= 2 1) +12-+3= 8 2 +12+-3= 15 3)-10--7=-17 4)-10++7= -17
 * A)Use the number line to find each difference. Use a chipboard to check your work.**
 * B)Use a number line to find each sum or difference.**


 * C) Find the difference between each pair of numbers on a number line. In each case, tell how the distance is related to the difference is related to the difference between the two numbers.**

**1)** 1 and 5 positive numbers are always on the right so we 4 spaces to the right.

2) -1 and 5 are both positive and negative numbers so we move on both sides of the number line, but because 5 is a larger amount of quantity the it will land on the right and you will move 6 spaces.

3)-5 and -9 are both are both negative numbers, so we stay on on the left side of the number line, we move 4 spaces so the answer should on the left side of 0.

4) -3 and 3 are both negative and positive numbers, so we go on both sides of the number line, 3+3= 6, so we move 6 spaces.

**F.U.**
No you can't get a negative number if you subtract a greater number from a smaller number, because if your subtracting more from a number than it is you go below 0 which is negative. 10- 10, -10 5- 5, -5 1- 1, -1 7- 7, -7
 * 1) **When you add two positive integers you get a positive sum . When you subtract two positive integers, do you always get a positive difference? Explain.**
 * 1) ======**When you use the number line model, you can think of the** // **absolute value** // **of a number as its distance from 0. For example, 3 and -3 are each 3 units from 0, so the absolute value of each number is 3. **======
 * Use a number line to help you find a pair of numbers with the given absolute value.**

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