CEREAL NUMBERS

GOALS

1. estimate, measure, & compute area & volume of rectangular prisms

2. estimate or compute the dimensions of a rectangular prism with a given volume

3. extract information from tables & graphical representations

4. use a visual model to multiply fractions

5. use a strategy to divide fractions within a context

6. understand the effect of changes related to dimensions, area, & volume

7. make comparisons using estimations or direct calculations with ratios, fractions, decimals, & percents

8. understand and use relationships among fractions, percents, decimals, & ratios

9. generalize procedures for determining volume

10. solve problems dealing with enlarging a volume by a factor

11. analyze & solve problems dealing with relative & absolute comparisons

SECTION SUMMARIES

SECTION A: POPCORN VOLUME

1. To understand a volume, it helps to describe the volume by length, width, and height.

2. For example, a rectangular prism that is 18 dm long, 17 dm wide, & 18 dm high has a volume of 5508 cubic decimetres.

SECTION B: MEASURING CORN

1. A ratio comparing corn grown by each state is an absolute comparison.

2. A ratio comparing corn production in relation to land area or population is a relative comparison.

3. A bar, ratio table, or number line is sometimes all you need to make and support an estimation, otherwise when an exact calculation is necessary, a calculator may be helpful too.

SECTION C: PACKAGE DIMENSIONS

1. If each dimension of a rectangular prism is increased by a factor of 2, the new volume is actually increased by

a factor of 8, not 6 as you might expect.

SECTION D: PERCENTS OF INGREDIENTS

1. We looked at percents as a way to measure ingredients of food products. We used ingredient triangles to visually compare recipes, but triangles such as these can also be used to compare other things.

SECTION E: FRACTIONAL AREAS

1. If you have to multiply numbers involving fractions, drawing a picture can help you find an estimate or an actual answer.

SECTION F: SERVING PROPORTIONS

1. If you have to do a division problem involving fractions, you can replace the fractions with whole numbers as

long as you use the same ratio in your division. for example 2½÷3 is the same as 5÷6, or .

SECTION G: PRICE COMPARISONS

1. The comsumer price index (CPI) is used to show changes in prices over time.

2. The first year of CPI prices are set at 100. Then other table entries are percent increases or decreases relative

to that year.