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Math Flash Rounding. 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. Memorize this Poem. Find your number. Look right next door. - PowerPoint PPT Presentation
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Math FlashMath FlashRoundingRounding
Use roundingUse 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.
Memorize this PoemMemorize this Poem
Find your number.Look right next door.4 or less just ignore.5 or more, add 1
more.
Use Place Value Carefully to Use Place Value Carefully to Round!Round!
1. Find the digit in the place you are asked to round to. (tens,
hundreds or thousands)2. Look right next door. Look at the
number in the place to the right! 3. If the number in the place to the
right is 4 or less “just ignore” and keep
the digit the same.4. If the number in the place to the
right is 5 or more, you add 1 more to
the digit.
Round this number to the Round this number to the nearestnearest
ten.ten.
Find your number.
657Circle the number in the tens
place.
Round this number to the Round this number to the nearestnearest
ten.ten.
Look right next door.
6 5 7Draw an arrow to the right of thenumber. Look at the ones place.
Round this number to the Round this number to the nearestnearest
ten.ten.
5 or more, add one more.
6 5 7 Since 7 is more than 5 we “round up”
and add one to the tens place.
Round this number to the Round this number to the nearestnearest
ten.ten.
5 or more, add one more.
6 6 0
Change the numbers in the ones place to 0’s.
The AnswerThe Answer
657 rounded to the nearest ten is
660
Round this number to the Round this number to the nearestnearest
ten.ten.
Find your number.
8 4 4Circle the number in the tens
place.
Round this number to the Round this number to the nearestnearest
ten.ten.
Look right next door.
8 4 4Draw an arrow to the right of thenumber. Look at the ones place.
Round this number to the Round this number to the nearestnearest
ten.ten.
4 or less, just ignore.
8 4 4 Since there is a 4 in the ones place, you “just ignore” and keep the tens
number the same.
Round this number to the Round this number to the nearestnearest
ten.ten.
4 or more, just ignore.
8 4 0 Change the numbers in the
ones place to 0’s and keep the number in the tens place the same.
The AnswerThe Answer
844 rounded to the nearest ten is
840
Round this number to the Round this number to the nearestnearest
hundred.hundred.
Find your number.
7, 2 2 1Circle the number in the hundreds
place.
Round this number to the Round this number to the nearestnearest
hundred.hundred.
Look right next door.
7, 2 2 1Draw an arrow to the right of the
number.
Round this number to the Round this number to the nearestnearest
hundred.hundred.
4 or less, just ignore.
7, 2 2 1
Since 2 is less than 4 we do not changethe 2.
Round this number to the Round this number to the nearestnearest
hundred.hundred.
4 or less, just ignore.
7,2 0 0
Change the numbers to the right of the 2 to 0’s.
The AnswerThe Answer
7221 rounded to the nearest hundred is
7,200
Round this number to the Round this number to the nearestnearest
thousand.thousand.
Find your number.
3 5, 3 2 7Circle the number in the thousands
place.
Round this number to the Round this number to the nearestnearest
thousand.thousand.
Look right next door.
3 5, 3 2 7Draw an arrow to the right of the
number.
Round this number to the Round this number to the nearestnearest
thousand.thousand.
4 or less, just ignore.
3 5, 3 2 7
Since 3 is less than 4 we do not changethe 5.
Round this number to the Round this number to the nearestnearest
thousand.thousand.
4 or less, just ignore.
3 5, 0 0 0
Change the numbers to right of 5 to 0’s.
The AnswerThe Answer
35,327 rounded to the nearest thousand is
3 5, 0 0 0
Round this number to the Round this number to the nearestnearestdollar.dollar.
Find your number.
$ 5. 8 7
Circle the number where the dollarsare.
Round this number to the Round this number to the nearestnearestdollar.dollar.
Look right next door.
$ 5. 8 7
Draw an arrow to the right of thecircled number.
Round this number to the Round this number to the nearestnearestdollar.dollar.
4 or less, just ignore.
$ 5. 8 78 is greater than 4 so go to the next
line of the poem.
Round this number to the Round this number to the nearestnearestdollar.dollar.
5 or more, add 1 more.
$ 5. 8 7Since 8 is greater than 5 add 1 to the
5.
+1
Round this number to the Round this number to the nearestnearestdollar.dollar.
5 or more, add 1 more.
$ 6. 0 0Change the 5 to a 6 and change all the
numbers to the right to 0’s.
The AnswerThe Answer
$5.87 rounded to the
nearest dollar is
$ 6. 0 0