Math 801A : Mathematical Operations – Decimal Fractions

1. Math 801A:Mathematical Operations – Decimal Fractions Mathematics Essentials March 2nd, 2017

2. Lesson Introduction Today I will... • use mental math and estimation strategies for operations involving integers and decimal fractions • apply mental math and estimation strategies in problem situations when appropriate • perform operations involving integers and decimal fractions in practice and problem situations using the most appropriate method

3. Decimal Fractions • In the “real world”, you wont always be able to work with whole number • You may need to work with parts of a whole such as decimalas • Particularly when a specific level of precision is required

4. Adding/Subtracting Decimal Fractions Step 1 – write the two numbers being added/subtracted with their decimal points aligned (zeros can always be included to represent place value). Step 2 – add/subtract the numbers as you would with whole numbers. Step 3 – place the decimal in the answer such that it is aligned with numbers being added/subtracted.

5. Practice Solve 1 A, C, D, F using: • Estimation • Pencil and paper

6. Multiplying Decimal Fractions • Performed in a similar way to mutipling whole numbers • Difference occurs in writing the resulting answer **When multiplying numbers containing decimals, the answer must contain the same number of decimal places as the sum of the decimal places in the two numbers being multiplied.

7. Practice Solve 3 A, B, C using: • Estimation • Pencil and paper

8. Dividing Decimal Fractions • Performed in a similar way to dividing whole numbers • Difference occurs in writing the resulting answer **When dividing numbers containing decimals by a whole number, the decimal point in the answer must align with the decimal in the number being divided

9. Practice Solve 3 D, E, F using: • Estimation • Pencil and paper

10. Homework! For tomorrow (Friday’s class): • Pg 20, q’s 5-8 • Pg 21, q’s 1+2