Mrs. Pilon's Math Page

Rounding and estimating.

Note:  you will need to do most of this assignment in your notebook or on looseleaf.  You may rewrite questions in vertical format.

1.  Round these numbers as indicated:
 

Number	Round to nearest 10	Round to nearest 100	Round to nearest 1000
6 528
9 455
13 647
56 495
88 009
368 555

2.  Now round these numbers as indicated:
 

Number	Round to nearest 10 000	Round to nearest 100 000	Round to nearest 1 000 000
2 652 311
3 486 299
13 586 931
9 326 000
8 493 224
972 000

3.  Add or subtract.
a.  6 000 + 19 000
b.  81 000 - 45 000
c.  97 000 – 16 000
d.  87 000 + 96 000

4.
 

Find the actual answer.	Estimate.
8 569 + 6 397 =	9000 + 6000 =
19 787 + 36 266 =
683 + 719 + 667 + 409 =
877 – 319 =
27 996 – 18 723 =

5.  Work out only those questions with an answer < 10  000.  (Hint:  estimate first.)

a.  9 738 + 1 007 =
b.  6 281 + 3 419 =
c.  14 678 – 5 426 =
d.  23 999 – 14 999 =

6.  Do only those questions with answers > 100 000.  (Hint:  estimate first.)

a.  36 851 + 67 533 =
b.  45 661 + 9 383 =
c.  123 456 – 2999 =
d.  532 111 – 389 232 =

7.  When you estimate by compensating, round the first numbers in the series normally.  Round the last one in the opposite direction.  This will give you a closer estimate.
 

Actual	Estimate by rounding	Estimate by compensating
453 + 571 + 882 + 476 =	500 + 600 + 900 + 500 =	500 + 600 + 900 + 400 =
56 + 29 + 49 + 55 =
713 + 639 + 122 + 541 =
231 + 842 + 843 + 125 =

8.  Read the following statements.  Then tell whether the answer is actual or an estimate.  How do you know which is which?

a)   Mount Everest is 29 000 feet tall.  ________________________
b)   Scientists tagged 5 739 Richardson’s Canada Geese one spring.  _________________________
c)  The circumference of Earth is 40 017 km.  __________________
d)  There are about 50 weeks in a year. ______________________
e)  Canada’s coastline is 28 737 km long.  _____________________
f)  The border Canada shares with USA is about 38 000 km long. __________________________
 

9.  Write the next 3 numbers in each pattern.  Be sure you can explain what the pattern is!

a)  3, 5, 7, __9__, _11_, ___13____  pattern:  +2
b)  1, 2, 4, 7, _________, _________, ___________  pattern: __________
c)  2, 4, 8, 16, __________, __________, __________ pattern:  ___________
d)  1, 4, 9, 16, ___________, ____________, ____________  pattern:  __________
e)  2, 4, 6, 8, __________, ____________, _____________  pattern:  ___________
f)  3, 5, 9, 17, ____________, _____________, _____________ pattern:  _________
g)  3, 6, 10, 15, _______________, _____________, ____________ pattern:  __________
h)  2, 5, 9, 14, _________, ______________, ____________  pattern:  ___________