Unit 4: Decimals, Percents and Ratios.

Section 11: Decimals

Goals:

Resources:
Decimal grids in SMART Notebook
Decimal grids in Microsoft Word
Bassarear discusses Decimals in section 5.4

Representing and comparing of decimals
Read:
In D2L->Content->Readings, read the article "Investigating Students' Conceptual Understanding of Decimal Fractions Using Multiple Representations"
Watch:
Decimals and place value.
Misconceptions and representations part 1; part 2.
Decimals in metric measurements.
Decimals on number lines.
Assignment
Do thisAssn 61: Draw or otherwise produce diagrams showing each of these decimals
a. in a grid
b. with base 10 blocks
c. on a number line. 
d. tell what length in centimeters or millimeters each represents if 1 means 1 m. (tell, don't draw)
(For example, in #1d, you should do: 0.68m=?cm  or 0.68m=?mm--choose which ever of cm or mm makes the most sense to use for the given amount)
1. 0.68
2. 0.4
3. 0.005

Fractions and decimals
Read:
D2L->Content->Readings->Relating Fractions and Decimals
Watch:

More misconceptions
Using a grid to convert fractions to decimals involves using a decimal grid, subdividing it into the appropriate fraction and then using the original grid to figure out the decimal representation for the amount.
Using division to convert fractions to decimals

Assignment
Do thisAssn 62: Converting fractions and decimals.

Operations on decimals:
Read:
D2L->Content->Readings->The Finger and the Moon
Reference on significant digits
Watch:
Explaining addition (and an extra example--very optional)
The difficulties of multiplication
An invented algorithm part 1, part 2.
Decimal multiplication with arrays part 1, part 2.
Things to know before you start dividing decimals: ways to handle remainders; significant digits.
Dividing decimals part 1, part 2;
And an optional ramble on remainders and dividing decimals.

Assignment:
Do thisAssn 63: Decimal operations