Is maths summations are very accurate?

If you wanted to calculate that, you would have to figure-in how the water affects the powder (plus whatever the kg-ltr factor is ... which I don't know, and would "Search the Web" above if I cared ). If you wanted to get really super-nerdy about it, then you COULD find a group of calculations that would be as precise as 'just measuring it,' but 'just measuring it' is usually quicker.

In algebra, we have the summation of like terms and unlike terms. If you have two or more like terms, you can add their coefficients just like you're adding a number. e.g: x+2x = 3x Unlike terms are usually left as they are. e.g: x+y = x+y analogically, in your case, water is not similar to powder. Therefore, both substance cannot be summed. (arithmetic summations are measurable) If you really want to perform summation of water and powder, the best mathematical concept would be set/field/group. so set A + set B = set (A+B) - set(A intersects B)

Hmmm i guess there is something u need to think about the question kilogram and liter is not in the same measure 1liter = 1 dm3 Means 1liter isnot equals to 1kg So the result may not 5 then

Now you know a liter is not the same as a kg when it is converted.

No & yes. No, the simple summation you're talking about may not be accurate; but that's because there are more variables in real life than are in your simple summation ... "There are more things in Heaven & Earth--Horatio--than are dreamt of in your philosophy." (William Shakespear's "Hamlet," I think)

The summations would be accurate if you used the same classification of measurement, or one that is common to both items in the equation. In the example you describe, one is a dry weight (kg) and one is a liquid volume (l), so they would not necessarily combine to make 5 of anything. You would need to either specify a new volume of the substance after the dry weight is added, or weigh the liquid and then add that weight to the 2kg. For example, water weighs about 8.3 pounds per gallon. I could not add 1 gallon of water to 2 pounds of sugar and get 3 pounds or 3 gallons. I could however add the 2 pounds weight of sugar to the 8.3 pounds weight of the water, and my container would now weigh 10.2 pounds.

Summations wouldn't be accurate if you think of it that way, which is why there are cross-formulas for solids and liquids and gases. These things are accurate if you know which one to use. I am not a mathematics expert but I do know that there are different formulas for different functions. Have a great MyLot experience ahead!