Question 5 options:
Is this number prime or composite?
57
composite
To determine if the number 57 is prime or composite, we need to check if it is divisible by any numbers other than 1 and itself.
First, let's check if 57 is divisible by 2. Since 2 is not a factor of 57, we continue to the next number.
Next, we check if 57 is divisible by 3. Summing the digits of 57 (5 + 7 = 12), we check if 12 is divisible by 3. Since 12 is divisible by 3, we know that 57 is also divisible by 3.
Therefore, 57 is a composite number, as it is divisible by both 3 and 19.
To determine whether 57 is prime or composite, we need to check if it has any factors other than 1 and itself.
To do this, we can start by dividing 57 by the smallest prime number, which is 2. If 57 is divisible by 2, then it is not prime. If it is not divisible by 2, we can move on to the next prime number, which is 3, and repeat the process. We continue dividing by prime numbers until we reach the square root of 57 or find a factor.
Let's perform the calculations:
57 ÷ 2 = 28 remainder 1
57 ÷ 3 = 19 remainder 0
Since 57 is divisible by 3 without a remainder, it is not prime. Therefore, 57 is a composite number.
To summarize, we determined that 57 is a composite number by dividing it with prime numbers up to its square root and finding a factor.