# How do you ESTIMATE numbers? Use the skill of ROUNDING.

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How do you ESTIMATE numbers? Use the skill of ROUNDING

When do I use rounding? When the question asks you to estimate. When the question asks “about how many”…? When an exact answer isn’t possible. When an answer is difficult to obtain.

Try to Estimate the number of bricks used to build this portion of a chimney.

15 Bricks tall 15 Bricks tall About 4 bricks long About 4 bricks long About 2 bricks wide About 2 bricks wide 15 x 4 x 2 = 120 bricks

68,00068,24269,000 The population of the Sioux Reservation was 68,242. To the nearest thousand, what was the population? 68,242 is between 68,000 and 69,000, but it is closer to 68,000.

9 8 7 6 5 4 3 2 1 +0 +1

Round this number to the nearest ten thousand. Find your number. 3 6 8,9 7 1 Underline the number in the ten thousands place.

Round this number to the nearest ten thousand. Look right next door. 3 6 8,9 7 1 Circle the digit to the right of the underlined number.

Round this number to the nearest ten thousand. 4 or less, just ignore. 3 6 8,9 7 1 8 is larger than 4 so go to the next line of the poem.

Round this number to the nearest ten thousand. 5 or more, add 1 more. 3 6 8,9 7 1 Add 1 to the 6. +1

Round this number to the nearest ten thousand. 5 or more, add 1 more. 3 7 0,0 0 0 Add 1 to the 6 and all the numbers to the right of the 7 become 0’s.

The Answer 368,971 rounded to the nearest ten thousand is 3 7 0,0 0 0

Round this number to the nearest thousand. Find your number. 3 5, 3 2 7 Underline the number in the thousands place.

Round this number to the nearest thousand. Look right next door. 3 5, 3 2 7 Circle to the right of the underlined number.

Round this number to the nearest thousand. 4 or less, just ignore. 3 5, 3 2 7 Since 3 is less than 4 we do not change the 5.

Round this number to the nearest thousand. 4 or less, just ignore. 3 5, 0 0 0 Change the numbers to left of 5 to 0’s.

The Answer 35,327 rounded to the nearest thousand is 3 5, 0 0 0

Round 73,852 to the nearest… 1. Ten-thousand. 2. Thousand. 3. Hundred. 4. Ten. 70,00074,00073,90073,850

Round this number to the nearest dollar. Find your number. \$ 5. 8 7 Underline the number where the dollars are.

Round this number to the nearest dollar. Look right next door. \$ 5. 8 7 Circle to the right of the underlined number.

Round this number to the nearest dollar. 4 or less, just ignore. \$ 5. 8 7 8 is greater than 4 so go to the next line of the poem.

Round this number to the nearest dollar. 5 or more, add 1 more. \$ 5. 8 7 Since 8 is greater than 5 add 1 to the 5. +1

Round this number to the nearest dollar. 5 or more, add 1 more. \$ 6. 0 0 Change the 5 to a 6 and change all the numbers to the right to 0’s.

The Answer \$5.87 rounded to the nearest dollar is \$ 6. 0 0

What about decimal numbers? The same rules (and poem) apply! Round 4.167 to the closest hundredths 4.167 Find your number Look right next door 4.17

Round 2.197 to the closes hundredths Since there is a “9” in the hundredths place consider the tenth and hundredths together – 19 – do you leave it at 19 or move it to 20?

Round 4.95 to the closest tenth Since there is a “9” in the tenth spot consider the ones and tenths together…… should you leave it at 49 or move it to 50? 4.95 rounded to the nearest tenth is 5.0

Try these Round to tenths: 4.564.6 5.325.3 0.981.0 Round to hundredths 18.78418.78 9.456 9.46 9.997 10.00

Round this number to the nearest tenth place. Find your number. 4. 8 7 1 Underline the number in the tenths place.

Round this number to the nearest tenth place. Look right next door. 4. 8 7 1 Circle to the right of the Underlined number.

Round this number to the nearest tenth place. 4 or less just ignore. 4. 8 7 1 8 is greater than 4 so go to the next line of the poem.

Round this number to the nearest tenth place. 5 or more, add 1 more. 4. 8 7 1 Since 7 is greater than 5, add 1 to the 8. +1

Round this number to the nearest tenth place. 5 or more, add 1 more. 4. 9 Change the 8 to a 9 and drop the numbers to the right of the 9.

The Answer 4.871 rounded to the nearest tenth place is 4. 9

The End Find your number. Look right next door. 4 or less just ignore. 5 or more, add 1 more.

Remember If you are asked to round to the nearest tenth…….your answer stops at the tenth place! Example: Round 42.73 to the closest tenth would be 42.7

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