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Rounding to the Nearest Hundred

When we round to the nearest hundred, the numbers “residing” in the red areas (up to 850) on the number line are rounded to 800. The numbers in the blue areas are rounded to 900.

Again, distance matters. Numbers from 801 to 849 are closer to 800 than to 900.
Numbers from 851 to 899 are closer to 900 than to 800. And the “middle guy,” 850, is rounded up to 900:   850 ≈ 900.

1. Mark the numbers as dots on the number line (approximately) and round them to either 800 or 900.

a.

804 ≈ ____________

859 ≈ ____________

b.

825 ≈ ___________

850 ≈ ___________

c.

860 ≈ ___________

847 ≈ ___________

d.

808 ≈ ___________

892 ≈ ___________

 

When rounding to the nearest hundred, look at the TENS DIGIT of the number.

  • If that digit is 0, 1, 2, 3, or 4, you will round down to the previous hundred.
  • If that digit is 5, 6, 7, 8, or 9, you will round up to the next hundred.
728 ≈ ?   The tens digit is 2, so round down:

728 ≈ 700

471 ≈ ?   The tens digitis 7, so round up:

471 ≈ 500

956 ≈ ?   The tens digit is 5, so round up:

956 ≈ 1000

2. Round these numbers to the nearest hundred.

a.

416 ≈ ___________

837 ≈ ____________

b.

529 ≈ ___________

960 ≈ ___________

c.

670 ≈ ___________

557 ≈ ___________

d.

254 ≈ ___________

147 ≈ ___________



Things work similarly on this number line when rounding to the nearest hundred:

  • Numbers up to 2,450 (the middle number) are rounded down to 2,400.
  • Numbers after 2,450 are rounded up to 2,500.
  • And the “middle guy,” 2,450, is rounded up.

3. Round these numbers to 2,400 or to 2,500. You can use the number line above to help you.

a. 2,412 ≈ __________ b. 2,429 ≈ __________
c. 2,478 ≈ ___________ d. 2,490 ≈ ___________

 

Rounding rules

When rounding to the nearest hundred, look at the TENS DIGIT of the number.

If the tens digit is 0, 1, 2, 3, or 4, you will round down to the previous hundred.

728 ≈ ?  The tens digit is 2, so round down:

728 ≈ 700

Notice: the hundreds digit does not change.

If that digit is 5, 6, 7, 8, or 9, you will round up to the next hundred.

471 ≈ ?   The tens digit is 7, so round up:

471 ≈ 500

Notice: the hundreds digit increases by one, from 4 to 5.

Whether you round up or down, the tens and ones digits change to zeros.

4. Round these numbers to the nearest hundred.

a.  6,216 ≈ _________ b.  5,923 ≈ _________

c.  1,670 ≈ _________

d.  8,254 ≈ _________

e.  8,019 ≈ _________ f.  2,157 ≈ _________

g.  1,772 ≈ _________

h.  6,849 ≈ _________

i.  801 ≈ _________ j.  255 ≈ _________

k.  9,562 ≈ _________

l.  3,501 ≈ _________



Note especially!    4,952 ≈ ?

Now the tens digit is 5, so we round up. The hundreds digit (9) increases by one (to ten hundreds). But we can't change 9 to 10 or we would get 41052!

Instead, those ten hundreds make a new thousand, so the thousands digit is incremented by one. It is as if '49' changes to '50'.   So, we get 4,952 ≈ 5,000

5. Round these numbers to the nearest hundred.

a.  6,986 ≈ _________ b.  5,973 ≈ _________
c.  1,981 ≈ _________

d.  4,945 ≈ _________
e.  2,932 ≈ _________ f.  9,969 ≈ _________
g.    966 ≈ _________ h.  9,982 ≈ _________
i.    798 ≈ _________


6. Round these numbers to the nearest hundred.
   Place each answer in the cross-number puzzle.


    Across:

    a. 2,264 ≈ _______

    b. 4,973 ≈ _______

    c. 4,248 ≈ _______

    d.  545 ≈ _______

Down:

e. 3,709 ≈ _______

f. 672 ≈ _______

g. 5,370 ≈ _______

h. 8,816 ≈ _______

a. e.        
           
b.          
          h.
f.   g.      
    c.      
           
  d.        


7. Fill in, using rounded numbers.

   a. Usually, Mary receives about __________ spam emails daily, but on 5/9 she got about ___________ spams.

   b. During the work week from 5/7 till 5/11 she received about __________ spams.

Spam Emails Mary Received

Date Spams round to nearest 100
Mo 5/7 125  
Tu 5/8 97  
Wd 5/9 316  
Th 5/10 118  
Fr 5/11 106  

See also

Free rounding worksheets
Generate free printable worksheets for rounding whole numbers for grades 2-6. The worksheets are customizable, randomly generated each time, and available as PDF or html files.




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