Business Mathematics Brief 12th Edition by Stanley Salzman ,Gary Clendenen, Charles Miller

Exercise 221

Eight rules of divisibility were given. Write the three rules that are most useful to you. (See Objective.)
Use the rules for divisibility. It is sometimes difficult to tell which numbers will divide evenly into another number. The following rules may help.
Quick TIP
There is not easy rule to see if a number is evenly divisible by 7.
Rules for Divisibility
A whole number can be evenly divided by
2 if the last digit is an even number, such as 0, 2, 4, 6, or 8
3 if the sum of the digits is divisible by 3 with no remainder
4 if the last two digits are divisible by 4 with no remainder
5 if the last digit is 0 or 5
6 if the number is even and the sum of the digits is divisible by 3 with no remainder
8 if the last three digits are divisible by 8 with no remainder
9 if the sum of all the digits is divisible by 9 with no remainder
10 if the last digit is 0