文档介绍：Math 302A
Section 4
January 23, 2007
Plan for class:
Investigation on page 131 in the green textbook.
Exploration : Part 1, questions 2 (you don’t have to write up different addition problems, but discuss in your group some different types of problems you e up with), 3, 5; Part 2, questions 3 (you don’t have to write up different subtraction problems, but discuss in your group some different types of problems you e up with), 4, 6. You will turn this in on Thursday.
Solve problems from (green) textbook: 9, 10, 13, 14 (page 147). You do not have to turn this in. If you didn’t get a chance to do these in class, you can still work on them for practice.
Homework:
Finish Exploration from class.
Read Section up to “Estimation.” Answer the following questions:
To add 23+ 45 + 67 + 55, I did the following: (23 + 67) + (45 + 55) = 90 + 100 = 190. Which properties of addition did I use?
Solve an addition problem using each of the strategies mentioned in the book: leading digit, compensation, break and bridge, patible numbers. Which do you prefer?
Explain the standard algorithm for addition. Explain why it works, not how to perform it. You can use concrete examples, manipulatives etc.
Important ideas from Section :
The number line as a model for representing operations on numbers.
Properties of addition: the identity, commutative, associative, and closure