You could use 250 and 750.
I would use 40 for the 38 and 50 for the 51. 90 would be my estimate.
You could use a demand chart to estimate this.
There is no means you can use to estimate it's
I would use 100/3.
how you would use the scale in miles to estimate to total area of Madagascar
805 and 1/ 3rd
The answer depends on what you want to use the estimate for. If it is being added to 1 billion, I would estimate it as 0. If adding to 25000, I would estimate it as 15000 and if adding to 0.075, I would leave it as it is.
The best measure to use is the meter. A kilometer would be well beyond the height of a desk or house.
You would use water displacement (ie volume)
The best unit to use to estimate the volume of a pepper shaker would be millilitres and not litres.So in the given example, the closest estimate would be 34 mL and not 34 L.
The front end estimate is 600. But estimating a single number, in isolation and without context, is a complete waste of time. If I had to add 558 to 1 trillion, I would estimate it as 0. If I had to add 558 to 0.0000000001, I would use the number as given - not use an estimate.Also, if I had to divide 558 by 5, I would estimate it as 560 since 560/5 = 112 whereas if I had to divide it by 30 I would go for 570 since 570/30 = 19.