Math1125NotesSept28PropOfMultiplicationDone.notebook
Homework Questions
October 07, 2012
Math1125NotesSept28PropOfMultiplicationDone.notebook
Properties of Multiplication:
Commutative Property of Multiplication:
If A and B are any real numbers then A*B = B*A.
What other operations are "commutative"?
What operations are not?
Now Do Activity 4F October 07, 2012
Math1125NotesSept28PropOfMultiplicationDone.notebook
October 07, 2012
Math1125NotesSept28PropOfMultiplicationDone.notebook
Associative Property of Multiplication
For all real numbers A,B and C (A*B)*C = A*(B*C)
What other operations have this property?
Name some that don't.
Now do Activity 4I (Especially # 1, 2, 4 , 6, 7)
October 07, 2012
Math1125NotesSept28PropOfMultiplicationDone.notebook
October 07, 2012
Math1125NotesSept28PropOfMultiplicationDone.notebook
October 07, 2012
Sec. 4.4 The Distributive Property of Mathematics
For any real numbers A, B and C, A x (B+C) = (A x B) + (A x C)
25 * 32 = 5 * 32 =
Now Do Activity 4 O #1 all parts.
Mental Multiplication
30*37
Mayan Multiplication Method
31*37
http://www.youtube.com/watch?v=zyE1EIMKq9k&feature=related
Math1125NotesSept28PropOfMultiplicationDone.notebook
October 07, 2012
Expresions that involve both Addition and Multiplication
7 + 3 * 2 =
5 x 17 + 92 ­ 12 x 3 + 20 / 5
Apply conventions:
1. Calculate Powers first
2. mulitplications and divisions performed left to right.
3. Additions and subtractions performed left to right.
4. Expressions inside parentheses are always evaluated first, using the previous conventions.
7 + 5 x 2 =
(7 + 5) x 2 =
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Bad "explanation" of the above problem.
http://www.youtube.com/watch?v=Kbw­B6Tb1hk&feature=related
Vi Hart Video about Mayan Mulitplication and the above problem
http://vihart.com/blog/visual­multiplication/
Math1125NotesSept28PropOfMultiplicationDone.notebook
1.
Problem 20 from Sec 2.6 – Suppose that 200 pounds of freshly pickled cucumbers are 99% water by weight. After several days, some of the water from the cucumbers has evaporated and the cucumbers are now 98% water by weight. How much do the cucumbers weigh now? Explain.
October 07, 2012