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 10 15,16, 17, 18, and 20, all become 20
Now, try to estimate to tens on your own
These are the right answers. How many did you get right?
ESTIMATING TO HUNDREDS When 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 , 161, 172, 183, 199, all go up to 200
Now, you try to round to hundreds ,4532,354 2,6543,765 7,3458,543 9,2309,999
How many did you get right? , ,4531,5002,354 2,300 2,6542,7003,765 3,800 7,3457,3008,543 8,500 9,2309,2009,999 10,000
Estimating Thousands When 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 1,000 2,500, 2,676, 2,765, and 2999 all become 2,000
Now, try to estimate to thousands 1,59832,456 3,46347,678 4,87569,087 5,70978,234 7,08912,909 4,32387,109 6,67590,534
How well did you do? 1,5982,00032,45632,000 3,4633,00047,67848,000 4,8755,00069,08769,000 5,7096,00078,23478,000 7,0897,00012,90913,000 4,3234,00087,10987,000 6,6757,00090,53491,000
Estimate these numbers to tens, hundreds, and thousands 7, 461 8,071 9,087 4,690
Did you get them right? 7, 461 7,4607, 5007,000 8,071 8,0708,1008,000 9,087 9,0909,1009,000 4,690 4,6904,7005,000