rounding is usually taken by rounding up anything equal to or above "5" and rounding down below "5" 52.61 ->the ".61" is above "5" and therefore you round up to 53
The inverse operation for subtract 5 is add 5. This is because whatever number you start with, if you first "subtract 5" and then "add 5" or if you first "add 5" and then "subtract 5" you are back to the number you started with.
A number ending in 0 does not require rounding. And 5 is half-way between 1 and 9.
When you round numbers you need to remember the rounding rules. If a number is 5 or above you round up. It a number is 4 or below you round down.So:2,570,2782,570,2802,570,3002,570,0002,570,0002,600,000
it depends if your rounding to the tenths then it is 4 and if your rounding to the whole number then it is 5
it rounds to that number because the number 4 is lower so they take that number out of the picture.
It is 5 when 4.6 is rounded to the nearest whole number.
I would give you the answer but to find it: Take the atomic number (the one ontop) and subtract it from the Atomic Mass number (the one on the bottom) -rounding is involved (5 & up round up, 4 & down round down!) Hope this helps.