With rounding:
is less than 
so we round it down to whole number:
is more than so we round it up to whole number:
Now we have to add rounded numbers
Without rounding:
to make it more visible I will write it differently:
is equal to
we can see that
is equal to 
so:
<span>As you see in this example those equations are equal so it doesn't matter if you take rounded numbers or not, it may be different in case like
( 
is just an example it could be any other number between 
) because in this case it will be equal 
and another example 
(in this case 
is just an example, it can be any other number between 
:) ) and here, answer for this equation is 
.</span>
Now we have to add rounded numbers
Without rounding:
we can see that
so:
<span>As you see in this example those equations are equal so it doesn't matter if you take rounded numbers or not, it may be different in case like