Estimation Strategies
In this rounding strategy, the first digit is always the "target digit" and everything else becomes zeros.
Example: 323 becomes 300.
1524 becomes 2000.
25 232 becomes 30 000.
Front End Rounding.
In this question, which place value is the 1 in?
31
Ones column
Write the number "three hundred seventy eight" in Standard form
378
Round this number to the nearest HUNDRED:
357
400
This estimation strategy, which starts with a C, is usually used when we're adding or subtracting more than two numbers. An example would look like this:
3245 + 1468 + 1235 + 8345
DOWN UP DOWN UP
3200 1500 1200 8400
Compensation
In this number, which place value is the 7 in?
1 734
Thousands column
Write the number
250 in expanded form.
200 + 50
Round this number to the nearest THOUSAND
8 935
9 000
This estimation strategy is when we choose to round to the nearest ten, hundred, thousand, or ten-thousand based on making the numbers as easy to work with as possible.
Compatible Numbers
In the following number? How much is the 4 worth.
14 325
4 000
Write 3000 + 500 + 70 + 3 in standard form.
3573
Round this number to the nearest TEN THOUSAND
13 596
14 000
If we use our math skills to calculate the actual answer, what "E" can we use to check whether or not we were right?
Estimation
In this number, which column is the 7 in?
7 500 000
Millions
Write the following number in standard form:
8 000 000 + 600 000 + 70 000 + 5 000 + 300 + 9
8 675 309
Round this number to the nearest TEN
423
420
"5 or more, let it soar! 4 or less, let it rest!" This "R" describes moving a target digit up, or keeping it the same, based on whether or not the number beside it is less or more than 5.
Rounding
384 245
Write the following in Expanded Form:
4 532
4 000 + 500 + 30 + 2
Round this number to the nearest THOUSAND
19 586
20 000