No 100 is not a reasonable estimate
900
900
Well, honey, if you wanna estimate the sum of 3149 rounding to the nearest thousand, you're looking at about 3000. It's not rocket science, just chop off those last two digits and call it a day. Keep it simple, sweetheart!
126.1429
The sum is 2.05 and you don;t need to estimate such a simple sum!
A reasonable estimate of the sum of 78 and 119 is 197.
6% of 883= 6% * 883= 0.06 * 883= 52.98
One estimate is 800 although there is really no need t estimate such a simple sum: it is 778.
A343316
2422
400
Estimate by rounding to the nearest ten.​ Then, find the sum.221122plus+33554455​_​_The estimated sum is nothing.
It is 61: you do not need to estimate a sum as simple as that!
It depends on your level of numerical skill. You can convert the decimal to an approximate fraction and estimate the sum of the two fractions, or you can convert the fraction to an approximate decimal and estimate the sum of the two decimals or, if you are more able you just estimate their sum directly.
1 and 883
There are infinitely many possible answers. Two such are 1*883 and 10*88.3