Date post: | 03-Jan-2016 |
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Rounding Numbers
Sometimes close enough is good enough!
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.
The rounding poem
Find your number
Look right next door
4 or less, just ignore
5 or more add one more!
Round this number to the nearestten
Find your number.
3 6 8Circle the number in the ten place.
Round this number to the nearestten .
Look right next door.
3 6 8
Draw an arrow to the right of the number.
Round this number to the nearestten.
4 or less, just ignore.
3 6 8
8 is larger than 4 so go to the nextline of the poem.
Round this number to the nearestten thousand.
5 or more, add 1 more.
3 6 8Add 1 to the 6.
+1
Round this number to the nearestten.
5 or more, add 1 more.
3 7 0Add 1 to the 6 and all the numbersto the right of the 7 become 0’s.
The Answer
368 rounded to the nearest ten is:
3 7 0
Round this number to the nearestthousand.
Find your number.
3 5, 3 2 7Circle the number in the thousandsplace.
Round this number to the nearestthousand.
Look right next door.
3 5, 3 2 7Draw an arrow to the right of thenumber.
Round this number to the nearestthousand.
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 nearestthousand.
4 or less, just ignore.
3 5, 0 0 0
Change the numbers to right of 5 to 0’s.
Round this number to the nearesthundred.
Find your number
1,3 7 2Circle the number in the hundred place
Round this number to the nearesthundred.
Look right next door.
1,3 7 2Draw an arrow to the right of thenumber.
Round this number to the nearesthundred.
4 or less, just ignore.
1,3 7 2 Draw an arrow to the right of thenumber.
Round this number to the nearesthundred.
5 or more, add 1 more.
1, 3 7 2Add 1 to the 3.
+1
The Answer
1,372 rounded to the nearest hundred is
1,400
Round this number to the nearestthousand.
Look right next door.
3,6 8 9
Draw an arrow to the right of the number.
Round this number to the nearestthousand.
4 or less, just ignore.
3,6 8 9
6 is larger than 4 so go to the nextline of the poem.
Round this number to the nearestthousand
5 or more, add 1 more.
3,6 8 9Add 1 to the 3.
+1
Round this number to the nearestthousand.
Find your number.
3,689Circle the number in thethousands place.
The Answer
3,689 rounded to the nearest thousand is
3,700
Let’s try these
Round to ten:
456 460
532 530
98 100
Round to hundred:
8784 8800
456 500
9097 9000
Now It is your Turn
Round to ten:
425
32
258
Round to hundred:
784
426
997