Which of the following numbers are divisible by 3?
168,681

Answer

To determine if the numbers 168 and 681 are divisible by 3, we will use the rule that states a number is divisible by 3 if the sum of its digits is divisible by 3.

### Step-by-Step Solution:

**Step 1: Check the number 168.**
- Write down the digits: 1, 6, and 8.
- Calculate the sum of the digits:
\[ 1 + 6 + 8 = 15 \]

**Step 2: Check if 15 is divisible by 3.**
- Divide 15 by 3:
\[ 15 \div 3 = 5 \]
- Since 5 is a whole number, 15 is divisible by 3.

**Conclusion for 168:**
- Since the sum of the digits (15) is divisible by 3, the number 168 is also divisible by 3.

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**Step 3: Check the number 681.**
- Write down the digits: 6, 8, and 1.
- Calculate the sum of the digits:
\[ 6 + 8 + 1 = 15 \]

**Step 4: Check if 15 is divisible by 3.**
- Divide 15 by 3:
\[ 15 \div 3 = 5 \]
- Since 5 is a whole number, 15 is divisible by 3.

**Conclusion for 681:**
- Since the sum of the digits (15) is divisible by 3, the number 681 is also divisible by 3.

### Final Answer:
Both numbers, 168 and 681, are divisible by 3.

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