Divisibility Rules

Front

What is the divisibility rule for 2?

Back

A number is divisible by 2 if its last digit is even (0, 2, 4, 6, or 8).

Front

What is the divisibility rule for 5?

Back

A number is divisible by 5 if its last digit is 0 or 5.

Front

What is the divisibility rule for 10?

Back

A number is divisible by 10 if its last digit is 0.

Front

What is the divisibility rule for 4?

Back

A number is divisible by 4 if the last two digits form a number that is divisible by 4.

Front

What is the divisibility rule for 6?

Back

A number is divisible by 6 if it is divisible by both 2 and 3.

Front

What is the divisibility rule for 9?

Back

A number is divisible by 9 if the sum of its digits is divisible by 9.

Front

What is the difference between prime and composite numbers?

Back

Prime numbers have exactly two distinct positive divisors (1 and itself), while composite numbers have more than two positive divisors.

Front

What is the definition of a composite number?

Back

A composite number is a positive integer that has at least one positive divisor other than one or itself.

Front

What is the definition of a prime number?

Back

A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.

Front

What is the sum of the digits of 555,509?

Back

The sum of the digits is 5 + 5 + 5 + 5 + 0 + 9 = 29.