If a number exactly divides two numbers separately, it must exactly divide their sum.
Consider a common factor of two numbers to check the divisibility of their sum:
If a number divides another number exactly, then it is considered to be a factor of the number.
Let the two numbers in consideration be and .
Let be the number that divides both these numbers exactly.
The sum of these two numbers is .
Hence is a factor of the sum of the two numbers consequently dividing the sum of two numbers exactly.
For eg: divides the numbers and exactly.
The sum of these two numbers is
divides exactly.
Hence the given statement is true.