Rules and exercises to estimate numbers to tens, hundreds, or thousands

Rounding to Tens

When estimating to tens look at the ones digit.

If the digit is 5 or more, the rounding goes up.

If the ones digit is 4 or less, the rounding goes down.

10, 11, 12, 13, and 14, all become 1015,16, 17, 18, and 20, all become 20

Now, try to estimate to tens on your own23 12134 23445 36556 82967 28388 50791 756

These are the right answers.How many did you get right?23 20 121 12034 30 234 23045 50 365 37056 60 829 83067 70 283 28088 90 507 51091 90 756 760

ESTIMATING TO HUNDREDSWhen estimating to hundreds, the tens digit

determine if the estimate goes up or down. Like in the rounding to ten, if the tens digit is

5 or more, the estimate goes up. If the tens digit is 4 or less, the estimate goes

down.

123, 135, 109, 149, all go down to 100150, 161, 172, 183, 199, all go up to 200

Now, you try to round to hundreds102 134145 187298 980875 8081,453 2,3542,654 3,7657,345 8,5439,230 9,999

How many did you get right?102 100 134 100145 100 187 200298 300 980 1,000875 900 808 8001,453 1,500 2,354

2,3002,654 2,700 3,765

3,8007,345 7,300 8,543 8,5009,230 9,200 9,999 10,000

Estimating ThousandsWhen estimating to thousands, the hundreds

digit is the one that determines if the number goes up or down.

If the hundreds digit is 5 or more the estimation goes up.

If the hundreds digit is 4 or less, the estimation goes down.

1,209, 1389, 1451, and 1499 all become 1,0002,500, 2,676, 2,765, and 2999 all become 2,000

Now, try to estimate to thousands1,598 32,4563,463 47,6784,875 69,0875,709 78,2347,089 12,9094,323 87,1096,675 90,534

How well did you do?1,598 2,000 32,456 32,0003,463 3,000 47,678 48,0004,875 5,000 69,087 69,0005,709 6,000 78,234 78,0007,089 7,000 12,909 13,0004,323 4,000 87,109 87,0006,675 7,000 90,534 91,000

Estimate these numbers to tens, hundreds, and thousands7, 461

8,071

9,087

4,690

Did you get them right?7, 4617,460 7, 500 7,0008,0718,070 8,100 8,0009,0879,090 9,100 9,0004,6904,690 4,700 5,000