Core Focus on Decimals& Fractions

Rounding Decimals

Lesson 1.2

Warm – up (page 7)1. In which place is the 7 in the following decimal: 2.741?

2. In which place is the 3 in the following decimal: 12.563?

Write the following decimals in word form:

3. 4.236

4. 6.09

5. 12.014

WRITE ON TIME TRACKER: Rounding Decimals. ISN pgs. 9 & 10

Correct worksheet – use pen!

1. Tenths 18. 6.442. Thousandths 19. 0.895313. Hundredths 20. 0.135894. two tenths5. nine thousandths6. seven hundredths7. eight hundredths8. six tenths9. seven ones10. 22.7411. 56.0112. 4.53613. 81.00814. six and nine hundred two thousandths15. fifty-two and seven tenths16. eighty-nine thousandths17. two and five thousandths

Rounding Decimals

I can round decimals to the nearest one, tenth, hundredth or thousandth.

Lesson 1.2

Rounding Decimals

1. Underline the digit to which you will round.

2. Look at the digit to the right of the underlined digit.

If the digit is 4 or less, the underlined numeralstays the same.

If the digit is 5 or greater, add one to the underlined

digit.

3. Rewrite the decimal. Stop after writing the rounded digit.

Example 1Round 0.59 to the nearest tenth.

Underline the number in the tenths place. 0.59

Look at the digit to the right of the It is 9.underlined digit.

If the digit is 5 or greater, add one 5 + 1 = 6to the underlined digit.

0.59 rounded to the nearest tenth is 0.6.

Example 2A newborn bird weighed 2.84 ounces. How muchdid the bird weigh to the nearest ounce?

Underline the digit you are rounding to. 2.84

Look at the digit to the right of the 8underlined digit.

If the digit is 5 or greater, add one 2 + 1 = 3to the underlined digit.

The baby bird weighed almost 3 ounces because 2.84 rounded to the nearest one is 3.

Example 3Terrell worked 15.25 hours last week. He is paid for each full hour he works. When he fills in his time card, he must fill in the hours to the nearest hour. What should he write for last week?

Terrell needs to round to the nearest one. 15.25

Look at the digit to the right of the underlined It is a 2.digit.

If the digit is 4 or less, the underlined digit stays the same.

15.25 rounded to the nearest one is 15.

Terrell needs to write 15 hours on his time card.

Example 4A gas station advertised the price of unleaded gas as $3.999 per gallon. Oksana said she paid $3.99 per gallon. Was she correct? Explain your reasoning.

Oksana needs to round to nearest hundredth (penny).3.999

Look at the digit to the right of the underlined digit. It is 9.

If the digit is 5 or greater, add a one to the 9 + 1 = 10underlined digit.

Because ten is not a single digit, continue rounding digits to the left until you do not get a ten. In this case, $3.999 rounded to the nearest penny (hundredth) becomes $4.00.

Oksana is not correct. She actually paidcloser to $4.00 per gallon of gas than $3.99.

Communication PromptWhy might grocery stores use rounding when determining the price of food based upon weight, like produce?

Practice

• ISN pages 9 & 10 (yes, both pages).

Exit Problems1. Round the decimal 3.45 to the nearest tenth.

2. Round the decimal 2.309 to the nearest one.

3. Round the decimal 56.997 to the nearest hundredth.

4. Round the decimal 31.9085 to the nearest thousandth.

3.5

2

57.00

31.909