Mathematical+Reflections,+p+66+0910

W.L.  Math 7B 23/04/10 **Big Idea** Negative numbers help us to model many real world situations.

Essential Question #4: How do I multiply and divide integers? Mathematical Reflection 4 1. Q: Write a strategy for multiplying two integers. Be sure to consider all possible combinations of positive integers, negative integers and 0. Verify your strategy by finding the following products. A: a. -13*7=-9 With multiplying you just have to remember that if you multiply 2 positive or 2 negative numbers you always get a positive answer and if you multiply positive times negative or negative times positive you always get a negative answer. b. 11*-20=-220 c. -12*0=0 If you multiply anything by 0 you always get 0. d. -18*-22=396

2. Q: Write a strategy for dividing 2 integers. Be sure to consider all possible combinations of positive integers, negative integers and 0. Verify your strategy by finding the following products. A: a. 126/-9=-14 With dividing the rules are almost the same as in multiplying. If you divide 2 positives or 2 negatives you always get a positive answer. If you divide a negative by a positive or a positive by a negative you will always get a negative answer. b. -36/-12=3 c. -2592/32=-81 d. 0/18=0 If you divide 0 by anything you always get 0, but if you divide any number by 0 you get undefined.

Summary In this investigation we learned how to multiply and divide integers. We learned that if you multiply or divide 2 negative or 2 positives than the answer will be a positive number. If you multiply or divide a negative by a positive or a positive by a negative the answer will be a negative number.