Divisibility Rules for 2, 4, and 10 Practice Problems

To determine if 16 is divisible by 2, we simply apply the divisibility rule for 2. According to this rule, a number is divisible by 2 if its last digit is an even number, meaning the last digit must be 0, 2, 4, 6, or 8.

• Step 1: Identify the last digit of the number 16. The last digit of 16 is 6.
• Step 2: Check if the last digit 6 is even. Since 6 is an even number, this means 16 satisfies the divisibility rule for 2.

Therefore, the number 16 is indeed divisible by 2.

The correct choice, according to this analysis, is:

Yes

To determine if 21 is divisible by 4, we apply the divisibility rule for 4.

The rule states that a number is divisible by 4 if the number formed by its last two digits is divisible by 4. Since 21 only has two digits, we consider the entire number.

Checking if 21 is divisible by 4:
We calculate $21 \div 4$.

The quotient is 5 with a remainder of 1, since $4 \times 5 = 20$ and $21 - 20 = 1$.

Since there is a remainder, 21 is not divisible by 4. According to the divisibility rule, if there is any remainder other than zero, the number is not divisible.

Therefore, the correct conclusion is that 21 is not divisible by 4, and thus the number 21 is not divisible by 4.

To determine if 42 is divisible by 2, we apply the divisibility rule for 2:

• According to the divisibility rule, a number is divisible by 2 if its last digit is one of the even digits: 0, 2, 4, 6, or 8.

Let's check the last digit of 42:

• The last digit of 42 is 2.

• The digit 2 is an even number.

Since 2 is even, it follows that 42 is divisible by 2.

Therefore, the answer to the problem is Yes, which corresponds to choice 1.

To determine if 61 is divisible by 10, we use the divisibility rule for 10:

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

Let's apply this rule to the number 61:

• The last digit of 61 is 1.
• Since 1 is not 0, 61 does not satisfy the divisibility rule for 10.

Therefore, we conclude that 61 is not divisible by 10.

Hence, the correct answer is: No.

To determine if the number 10 is divisible by 4, follow these steps:

• Step 1: Perform Division
  Divide 10 by 4. Calculate $\frac{10}{4}$.
• Step 2: Check Result for Integer
  If $\frac{10}{4} = 2.5$, the result is not an integer.
• Step 3: Confirm Remainder
  Determine the remainder when 10 is divided by 4. $10 \div 4$ gives a quotient of 2 and a remainder of 2.
• Step 4: Conclusion on Divisibility
  Since there is a remainder, 10 is not divisible by 4.

Therefore, the number 10 is not divisible by 4. The correct answer is No.