Core Focus on Decimals & Fractions Rounding Decimals Lesson 1.2

Warm-Up 1.Round 16 to the nearest ten. 2.Round 320 to the nearest hundred. 3.Which numeral is in the tenths place in the decimal, 3.78? 4.Which numeral is in the hundredths place in the decimal, 4.691?

Rounding Decimals 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 numeral stays 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 1 Round 0.59 to the nearest tenth. Underline the number in the tenths place.0.59 Look at the digit to the right of theIt is 9. underlined digit. If the digit is 5 or greater, add one5 + 1 = 6 to the underlined digit rounded to the nearest tenth is 0.6.

Example 2 A newborn bird weighed 2.84 ounces. How much did the bird weigh to the nearest ounce? Underline the digit you are rounding to.2.84 Look at the digit to the right of the8 underlined digit. If the digit is 5 or greater, add one2 + 1 = 3 to the underlined digit. The baby bird weighed almost 3 ounces because 2.84 rounded to the nearest one is 3.

Example 3 Terrell worked 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 Look at the digit to the right of the underlinedIt is a 2. digit. If the digit is 4 or less, the underlined digit stays the same rounded to the nearest one is 15. Terrell needs to write 15 hours on his time card.

Example 4 A 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) 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 the9 + 1 = 10 underlined 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 paid closer to $4.00 per gallon of gas than $3.99.

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

Exit Problems 1.Round the decimal 3.45 to the nearest tenth. 2.Round the decimal to the nearest one. 3.Round the decimal to the nearest hundredth. 4.Round the decimal to the nearest thousandth