Decimal Place Value and Estimation

Test Friday, 9-19-08

• You will need a pencil and a piece of paper before you begin this presentation.

Vocabulary:

• Clustering• Indicated place value• Rounding• Estimate• Difference• Compatible numbers• Nearest whole (tenth, hundredth …)

Estimate by rounding to the nearest whole number:

• 4.218 + 6. 321

Answer:

• about 10

• Work: In order to round to the nearest whole number, look at the tenths place. (Rule 5 or more round up one, 4 or less stay the same.

• 4.218 + 6. 321 4 + 6=10

Estimate by rounding to the nearest tenth.

• 4.723 + .888

Answer:

• 5.6

• Work: to round to the nearest tenth, look at the hundredths place. (Rule 5 or more up, 4 or less stay the same)

• 4.723 + .888 4.7 + .9 = 5.6

Use clustering to answer the following:

• Three puppies have the following weights: 3.11 pounds, 2.98 pounds, and 2.96 pounds. Use clustering to determine their approximate total weight.

Answer:

• About 9 pounds

• Work: (Clustering- round all numbers to the same value)

• 3+3+3 = 9 (all the numbers are about 3)

Estimate the quotient by using compatible numbers.

• 65.23 divided by 8.001

Answer:

• 8

• Compatible Numbers: (make two numbers easier to divide.)

• 65.23 divided by 8.001 • 64 divided by 8 is 8

Review:

• Write the following in word form:• 5.35• 6.98

Answers:

• Five and thirty five hundredths

• Six and ninety eight hundredths

Write the following in Expanded form:

• 4.177

Answer for 4.177

• 4+.1+.07+.007

• Hint: Remember your chart

4

.1

.07 .007

Order the following numbers from least to greatest.

• 5.769, 5.84, 5.41, 5.7694

Answer for: 5.769, 5.84, 5.41, 5.7694

• 5.41, 5.769, 5.7694, 5.84

• Hint: Remember to look at the whole number, then tenths, hundredths, thousandths and ten thousandths

• Do not forget to study your worksheets I gave you, and your flip book.

• Do not forget to play Jeopardy. • Good Luck on your test.