Decimals (Day 1)

Place Thousands Hundreds Tens Ones . Tenths Hundredths Thousandths

Place Value

1,000 100 10 1 1/10 1/100 1/1000

With whole numbers and decimals, the value of each digit in a decimal is the product of the digit and its place value

8052.468

8,000 50 2 .4 .06 .008

Digit: 8 Value: 8,000 or .008

Decimals (Day 1)

Try It:

Give the value of each 1:

316.24

587.13

Give the value of each 3:

316.24

587.13

Decimals (Day 1)Read 8,052.468

1. Read the whole number: “Eight thousand fifty two”2. Read the decimal:“and”3. Read the decimal values (say the last value):“four hundred sixty eight thousandths”

8,052.468 = “Eight thousand fifty two and four hundred sixty eight thousandths”

Decimals (Day 1)

Try It:

Read: 42.68

Read: 634.16

Read: 46,600.661

Decimals (Day 1)

Compare 3.75 and 3. 9

To compare and order decimals, write the numbers with their decimal points lined up. Then compare the digits in each place from left to right.

3.75

3.903.75 < 3.9

Decimals (Day 1)

Try It:

Use < , > , = to compare each set of numbers.

387.65 387.56

17.341 17.3409

53.31 53.310

Homework: Lesson 3-1 (#31-24)

Decimals (Day 2)

Before solving an addition or subtraction problem using decimals you may want to estimate a solution using simpler numbers.

Example #1: 14.779 + 20.24Round to the nearest whole numbers: 15 + 20 = 35Estimation: 14.779 + 20.24 35

Example#2: 67.54 – 32.45Round to the nearest whole number: 68 – 32 = 36Estimation: 67.54 – 32.45 36

Decimals (Day 2)

Adding and Subtracting Decimals:

1. Write the numbers with their decimal point lined up. (This lines up the place values)

2. Annex zeros as needed.

3. Add or subtract digits.

4. Place the decimal point in the answer.

Decimals (Day 2)

Example #3:

9.55 + 8.39 =

Estimate: Solve:

10 + 8 18 9.55

+ 8.39

17.94

Decimals (Day 2)Put it all together! Solve:

x – 4.5 = 8.6

n + 16.05 = 37.4

j + 2.75 = 11.3

k – 12.87 = 3.6Homework: Lesson 3-3

(#2-38 evens)