You can use the method of casting out nines to check your arithmetic by applying the fol...

You can use the method of casting out nines to check your arithmetic by applying the following reasoning. If a is any whole number and a* is the

Thus, the sum appears to be correct.

a. Use the method of casting out nines to check the following addition problem.

b. Does verifying the congruence mod 9 by casting out nines guarantee that a sum has been calculated correctly? Explain and give an example.