The whole numbers are not closed under subtraction. Why?

Find the sum of $837+208+363$ by suitable rearrangement.

Find the sum of $1962+453+1538+647$ by suitable rearrangement.

Find the following product by suitable rearrangement:

$2\times 1768\times 50$.

Find the product by suitable rearrangement.

$4\times 166\times 25$

Find the product by suitable rearrangement:

$8\times 291\times 125$
 

Find the product of $625\times 279\times 16$ by suitable rearrangement.