Adjust a little higher for an estimate of 55. Calculate the sum of the rounded numbers. This is where you make a long number simpler by rounding or expressing in terms of the nearest unit ten hundred tenth or a certain number of decimal places.
Once youve rounded the numbers you can estimate the answer in your head.
You look at the last digit in each number If the last number is 5 then round off to the nearest 0 If the last number is 5 then round off to the nearest 10 You can estimate products and quotients as well. Look at the amount of rounding. 298 is nearly 300 so an estimate is 550300 850. Rounding makes math problems.