Your sum might be less than fifty and you would rather round to forty than zero.
Money values, when the amounts are in the major currency units (Euros, or Pounds or Dollars etc), sprint times for 100 metres, measured in seconds. Basically in any situation where rounding to a tenth may result is a serious loss of detail.
"Kilogram" is not a unit of weight. It's reasonable to expect that a cat might have a mass of four kilograms.
Two hundred and two hundred two thousandths - or you could slightly simplify it to be two hundred and one hundred one five hundredths since 0.202 = 101/1000. Because of the ambiguity of the way it is written you might consider hyphenating it to read "Two-hundred and two-hundred-two thousandths". It might not be absolutely correct, but it will make it clear to someone reading how to group the words.
0
A reasonable estimate might be 6000 x 90 = 540000
The answer might depend on what you mean by "tn hundred".
200
The front end estimate is 1000. But estimating a single number, in isolation and without context, is a complete waste of time. If I had to add 1374 to 1 trillion, I would estimate it as 0. If I had to add 1374 to 0.0000000001, I would use the number as given - not use an estimate.Also,if I had to calculate 1374/13 I might estimate it by 1365 because 1365/13 = 105 can be calculated mentally.
Money values, when the amounts are in the major currency units (Euros, or Pounds or Dollars etc), sprint times for 100 metres, measured in seconds. Basically in any situation where rounding to a tenth may result is a serious loss of detail.
I could tell you where the nearest gas station to ME is, but that wouldn't do you much good. You might try Google maps instead.
300
The front end estimate is 3. But sometimes 7/2 ( = 3.5) might be better.
It depends how you round. 1160 rounded to the nearest hundred is 1200. 1198 rounded to nearest tens is also 1200.
Rounding is a way of simplify an exact number to make it easier to understand or remember. For example, the population of a city might be 71,212. To nearest thousand, this number is 71,000 which may be close enough for your purposes. To nearest hundred, it is 71,200 which is more accurate. Estimating is educated guessing, based on experience, visual observations, or rough calculations or other information. I might estimate the population of a city by driving around in it, counting the houses, studying a city map , aerial photograph or telephone directory or considering other information.
The front end estimate is 30. But estimating a single number, in isolation and without context, is a complete waste of time. If I had to add 33 to 1 trillion, I would estimate it as 0. If I had to add 33 to 0.0000000001, I would use the number as given - not use an estimate. Also, for multiplication, I might estimate it by 33.33... and then use 100/3 for calculations.
No 100 is not a reasonable estimate
1395.000