Rounding
Estimating sums and differences
Multi-Digit Adding
Multi-Digit Subtracting
Tricks and Puzzles
100

Round this number to the nearest hundreds place.

1, 882

1, 800

100
Estimate to the nearest hundreds place to find the sum.


316 + 632


300 + 600 = 900

100

540,540 + 998,998 = 

1,539,538

100

987,654 - 876,543 = 

    987,654

-   876,543

    111,111

100

If there are 4 apples on the back counter of Ms. Norby's room and you take away 3, how many apples do you have?

3

200

Round this number to the nearest tens place.

1,234,567

1,234,570

200

Estimate to the nearest thousands place to find the difference.

5,282 - 2,578

5,000 - 3,000 = 2,000

200

652,230,950 + 1 = 

  652,230,950

+                1

652,230,951

200

5,133 - 4,124 =

  5,133 

- 4,124

  1,009

200

Free money- however, if you get this riddle right, you will double this free money.

 If two math books were complaining, what would they say to each other?

I have way too many problems.

300

Round this number to the nearest thousands place.

58, 205

58,000

300

Estimate to the nearest thousands place to find the difference.

20, 654 - 15, 987

21,000 - 16,000 = 5,000

300

555,555 + 555,555 =

 555,555

+555,555

1,111,110

300

3,242 - 2,143 = 

   3,242

-  2,143

   1,099


300

How many sides does a circle have?

0

400

Round this number to the nearest ten thousands place.

654,321

650,000

400

Estimate to the nearest thousands place to find the sum.

40, 628 + 3, 123

41,000 + 3,000 = 44,000


400

2,394,086 + 1,452,923 =

   2,394,086

+ 1,452,923

   3,847,009

400

13,421 - 3,332 =

  13,421

-  3,332

  10,089

400

If you multiply this number by any other number, your answer will always be the same. What number is this/


0 x 5 = 0

 0 x 100 = 0

533 x 0 = 0

500

Round this number to the nearest hundreds place.

987

1,000

500

Estimate to the nearest millions place to find the sum.

6,543,210 + 9,876,543

7,000,000 + 10,000,000 = 17,000,000

500

488,000 + 62,123 =

  488,000

+ 62,123

550,123

500

50,032 - 42,142

  50,032 

- 42,142

7,890

500
What weighs more?

A pound of feathers or a pound of bricks?

Each are one pound so they weigh the same!