Math 247 Unit 2: Base 10 numbers and algorithms

Section 7: Multiplication and division algorithms.

Goal: The goals this week are for you to


Assignments: Please scan as necessary, and put all assignments in the dropbox.


Paths to the standard algorithm:

Read and watch this discussion of breaking down multidigit multiplication using arrays and the distributive law, and recording multiplication using the expanded and the standard algorithm. (note: this page includes links to several videos, and hence is longer than it appears).

Assignment 33: Expanded and standard algorithms assignment 

Mental math and the lattice algorithm:

Read and watch this discussion of mental multiplication strategies and the lattice algorithm.

Assignment 34: Mental arithmetic multiplication and the lattice algorithm

Error patterns

Assignment 35: Figure out the error patterns and identify the alternate algorithms in the assignment Multiplication error patterns and algorithms


Partitive division and long division

Do first: open the base 10 blocks Smart notebook (see resources), and use them to divide 860 6 using a partitive interpretation (make 6 groups)


Assignment 36: Manipulatives and partitive long division assignment (video)

Measurement division and the scaffolding algorithm



Assignment 37: Scaffolding division assignment

Why can't you divide by 0?


3 reasons you can't divide by 0
The problem with dividing 0 by 0

Read: Bassarear 4th ed pg 193 (3rd ed. pg. 188)


Assn 38: Write or record on video a good explanation of why you can't divide 10 by 0.
Error patterns

A common and recalcitrant error

Assignment 39: Do the assignment Division error patterns and algorithms