Rounding Numbers to the Nearest Ten, Hundred, and Thousand • Instructional Objective: – To Investigate and develop an understanding of the base ten place.
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Rounding Numbers to the Nearest Ten, Hundred, and Thousand • Instructional Objective: – To Investigate and develop an understanding of the base ten place value system
What is rounding numbers?
You can estimate when you need to know about how many or about how much. Rounding is one way to estimate.
Rounding to the Nearest Ten
You estimate which ten the number you are rounding is closest to. If you saw a road sign that said Flint was 17 miles away, then you could say that Flint is about 20 miles away. Flint 17 miles 10 11 12 13 14 15 16 17 18 19 20 17 rounds to 20 Because 17 is closer to 20 than 10
Look at these examples. Try to determine what the rule is for rounding to the nearest ten.
What does 12 round to?
What does 93 round to?
What does 15 round to?
What does 77 round to?
What does 22 round to?
Choose the rule: If the number in the ones column is 0, 1, 2, 3, or 4 then round up to the greater ten.
If the number in the ones column is 0,1,2,3, or 4, then round down to the lesser ten.
Yes!! You are correct. When a number has a 0, 1, 2, 3, or 4 in the ones column you round to the lesser ten! For example 83 rounds to 80.
Think of rounding like a car going over a hill. If you are to round 54 to the nearest ten, then your choices are either round back to 50 or up to 60. You always need to look at the number in the ones column. If the car goes up to 54 and stops, then it will roll back to 50. 54 rounds to 50
54 55 53 50 51 52 56 57 58 59 60
Here is another example. If you are to round 87 to the nearest ten, then your choices are either round back to 80 or up to 90. If the car goes to 87 and stops, then it will roll to 90.
87 rounds to 90
80 81 82 83 84 85 86 87 88 89 90
Now it’s your turn to round to the nearest ten!
Round 32
35
30
40
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Now it’s your turn to round to the nearest ten!
Round 67
70
100
60
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Now it’s your turn to round to the nearest ten!
Round 25
20
50
30
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Next you will learn about rounding to the nearest hundred.
When rounding to the nearest hundred, you are finding out which hundred a number is closest to.
Rounding to the Nearest Hundred Swartz Creek 230 miles You estimate which hundred the number you are rounding is closest to. If you saw a road sign that said Swartz Creek was 230 miles away, then you could say that Swartz Creek is about 200 miles away. 200 210 220 230 240 250 260 270 280 290 300 230 is closer to 200 230 rounds to 200
Look at these examples. Try to determine what the rule is for rounding to the nearest hundred.
241 rounds to 200 532 rounds to 500
Choose the rule: If the number in the tens column is 0, 1, 2, 3, or 4 then round up to the greater hundred.
If the number in the tens column is 0,1,2,3, or 4, then round down to the lesser hundred.
Sorry.
Look at the numbers in the tens column. Do they cause the number to be rounded to the lesser hundred or the greater hundred?
Yes!! You are correct. When a number has a 0, 1, 2, 3, or 4 in the tens column you round to the lesser hundred! For example 429 rounds to 400.
Look at these examples. Try to determine what the rule is for rounding to the nearest hundred.
381 rounds to 400 262 rounds to 300 958 rounds to 1000
Choose the rule: If the number in the tens column is 5, 6, 7, 8, or 9 then round up to the greater hundred. If the number in the tens column is 5, 6, 7, 8, or 9 then round down to the lesser hundred.
Sorry.
Look at the numbers in the tens column. Do they cause the number to be rounded to the lesser hundred or the greater hundred?
• Yes!! You are correct. When a number has a 5, 6, 7, 8, or 9 in the tens column you round to the greater hundred!
Remember the example of the car going over the hill.
When rounding to the nearest hundred, any number that ends in 49 or less will cause the car to roll back to the lesser hundred and any number that ends in 50 or greater, will cause the car to roll up to the greater hundred.
If you round 720 to the nearest ten, then your choices are either round back to 700 or up to 800. If the car goes up to 720 and stops, then it will roll back to 700.
720 rounds to 700 730 740 720 710 700 750 760 770 780 790 800
Here is another example. If you round 360 to the nearest hundred, then your choices are either round back to 300 or up to 400. If the car goes to 360 and stops, then it will roll to 400.
360 rounds to 400 300 310 320 330 340
350 360 370 380 390 400
Now it’s your turn to round to the nearest hundred!
Round 236
200
300
400
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or 9, then round up.
Yes!! You are correct.
Round to the nearest hundred.
Round 581
500
550
600
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Round to the nearest hundred.
Round 749
600
700
800
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Last you will learn to round to the nearest thousand!
When you round to the nearest thousand you are estimating which thousand the number is closest to.
Rounding to the Nearest Thousand Posen 2600 miles You estimate which thousand the number you are rounding is closest to. If you saw a road sign that said Posen was 2600 miles away, then you could say that Posen is about 3000 miles away.
2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 2600 rounds to 3000 2600 is closer to 3000 than 2000
Look at these examples. Try to determine what the rule is for rounding to the nearest thousand.
2 4 56 rounds to 2000 5 3 02 rounds to 5000 3 2 89 rounds to 3000 7 3 67 rounds to 7000 8 4 22 rounds to 8000 7 0 56 rounds to 7000 1 2 45 rounds to 1000 9 1 35 rounds to 9000
Choose the rule: If the number in the hundreds column is 0, 1, 2, 3, or 4 then round up to the greater thousand.
If the number in the hundreds column is 0,1,2,3, or 4, then round down to the lesser thousand.
Sorry.
Look at the numbers in the hundreds column. Do they cause the number to be rounded to the lesser thousand or the greater thousand?
Yes!! You are correct. When a number has a 0, 1, 2, 3, or 4 in the hundreds column you round to the lesser thousand! For example 8368 rounds to 8000.
Look at these examples. Try to determine what the rule is for rounding to the nearest thousand.
4 5 89 rounds to 5000 6 9 00 rounds to 7000 8 9 54 rounds to 9000
Choose the rule: If the number in the hundreds column is 5, 6, 7, 8, or 9 then round up to the greater thousand.
If the number in the hundreds column is 5, 6, 7, 8, or 9 then round down to the lesser thousand.
Sorry.
Look at the numbers in the hundreds column. Do they cause the number to be rounded to the lesser thousand or the greater thousand?
• Yes!! You are correct. When a number has a 5, 6, 7, 8, or 9 in the hundreds column you round to the greater thousand!
Let’s look at the hill again. If you are to round 6300 to the nearest thousand, then your choices are either round back to 6000 or up to 7000. If the car goes up to 6300 and stops, then it will roll back to 6000. 6300 rounds to 6000
6000 6100 6200 6300 6400 6500 6600 6700 6800 6900 7000
Here is another example. If you are to round 2900 to the nearest thousand, then your choices are either round back to 2000 or up to 3000. If the car goes to 2900 and stops, then it will roll to 3000.
2900 rounds to 3000
2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000
Now it’s your turn to round to the nearest thousand!
Round 5798
5800
6000
5000
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Now it’s your turn to round to the nearest thousand!
Round 2045
2000
2050
2100
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or9, then round up.
Yes!! You are correct.
Now it’s your turn to round to the nearest thousand!
Round 9430
8430
8400
9000
Sorry. Remember the rules: 1. If the number you are rounding is followed by a 0, 1, 2, 3, or 4, then round down .
2. If the number you are rounding is followed by a 5, 6, 7, 8, or 9, then round up.
Yes!! You are correct.