1. Fractions, Decimals and Percents Mini-course Session Five Developing Decimal Concepts

2. Objectives To use paper strips and base ten blocks as manipulatives for illustrating decimal concepts. To explore decimal notation, comparing decimals, and addition & subtraction with decimals. To become familiar with the NCTM Technology Principle.

3. Introduction to Base Ten Blocks and Number strips What is the connection between decimals and fractions? How might you use money to help your child learn about decimals? Number Strips and Base Ten Blocks are also used to illustrate decimal concepts.

4. Decimal Concepts Define each term: Decade Decimeter Decagon Decathlon -- 10 years -- One-tenth of a meter -- A ten-sided shape -- An Olympic event consisting of 10 contests What do these words have in common?

5. Decimal Strips Cut out and label the decimal strips Label one strip with fractions and one with decimals (See sample on overhead.) What is the decimal name for the spot halfway between 0.7 and 0.8? How did you determine this?

6. Decimal Strips Divide the strip into ten equal parts, making 100 parts in the entire strip. Where is the mark for 0.75? Explain

7. Decimal Strips Where is the mark for 0.20? How does the relationship between 0.2 and 0.20 relate to prior experiences with fractions? Partner up: Person #1 picks a two-digit decimal and person #2 reads the decimal using “hundredths.” Switch.

8. Decimal Strips 0.6 versus 0.06 What is the difference between these two values?

9. Decimal Strips How would we name a spot located between two of the hundredths lines we have drawn? What would the numerical notation look like? How would we read such a decimal? Where would we find 0.437 or 0.291 or 0.58316219? What logic is necessary to locate any decimal on the number line? At your tables…

10. Which is Larger? 0.45 or 0.71 0.8 or 0.24 0.05 or 0.5 0.734 or 0.73 0.02 or 0.020 0.5931 or 0.6 SAVE the fraction & decimal strips in your folders to use again next week!

11. Base Ten Blocks Number strips give a length model or number line representation for decimals. Base Ten Blocks provide an area model. A flat represents one whole, the long can represent tenths, and the units can represent hundredths

12. Base Ten Blocks Use the base ten blocks to represent the following decimal values: 1.4 0.65 2.31 3.20 Can you represent the numbers in more than one way???

13. Model Using base ten blocks model: 1.5 + 2.44 Do the same for: 2.8 + 0.63 How do these two problems differ? What does regrouping mean?

14. If time permits….. 2.51 + 2.14 1.78 + 0.53 2.67 - 0.53 3.33 – 1.11 3.33 – 2.79 4.2 – 4.15 1.96 - 0.99 Make up your own!

15. NCTM Technology Standard www.nctm.org/families www.visualfractions.com Technology is essential in teaching and learning mathematics; it influences the mathematics that is taught and enhances participant learning.

16. Closure Reflect on the following: Something I Learned Something I Wonder Something I Want to Share with My Family Homework: Bringing Mathematics Home 5 Decimal Problems I