Divisibility Check
1. **State the problem:** Determine whether each number (88, 48, 22, 132, 264) is divisible by 4, 8, 11, and 12.
2. **Recall divisibility rules:**
- Divisible by 4: The last two digits form a number divisible by 4.
- Divisible by 8: The last three digits form a number divisible by 8.
- Divisible by 11: The difference between the sum of digits in odd positions and the sum of digits in even positions is 0 or a multiple of 11.
- Divisible by 12: The number is divisible by both 3 and 4.
3. **Check each number:**
**1) 88**
- Last two digits: 88, divisible by 4 since $88 \div 4 = 22$.
- Last three digits: 88 (only two digits), check 8 divisibility: $88 \div 8 = 11$, divisible.
- Sum of digits: $8 + 8 = 16$, divisible by 3? No.
- Divisible by 12? No, since not divisible by 3.
- For 11: Odd positions digits = 8 (1st), Even positions digits = 8 (2nd), difference $8 - 8 = 0$, divisible by 11.
**2) 48**
- Last two digits: 48, divisible by 4 since $48 \div 4 = 12$.
- Last three digits: 48, check 8 divisibility: $48 \div 8 = 6$, divisible.
- Sum of digits: $4 + 8 = 12$, divisible by 3.
- Divisible by 12? Yes, divisible by 3 and 4.
- For 11: Odd positions digits = 4, Even positions digits = 8, difference $4 - 8 = -4$, not divisible by 11.
**3) 22**
- Last two digits: 22, check divisibility by 4: $22 \div 4 = 5.5$, not divisible.
- Last three digits: 22, check divisibility by 8: $22 \div 8 = 2.75$, not divisible.
- Sum of digits: $2 + 2 = 4$, not divisible by 3.
- Divisible by 12? No.
- For 11: Odd positions digits = 2, Even positions digits = 2, difference $2 - 2 = 0$, divisible by 11.
**4) 132**
- Last two digits: 32, divisible by 4 since $32 \div 4 = 8$.
- Last three digits: 132, check divisibility by 8: $132 \div 8 = 16.5$, not divisible.
- Sum of digits: $1 + 3 + 2 = 6$, divisible by 3.
- Divisible by 12? No, since not divisible by 8.
- For 11: Odd positions digits = 1 + 2 = 3, Even positions digits = 3, difference $3 - 3 = 0$, divisible by 11.
**5) 264**
- Last two digits: 64, divisible by 4 since $64 \div 4 = 16$.
- Last three digits: 264, check divisibility by 8: $264 \div 8 = 33$, divisible.
- Sum of digits: $2 + 6 + 4 = 12$, divisible by 3.
- Divisible by 12? Yes, divisible by 3 and 4.
- For 11: Odd positions digits = 2 + 4 = 6, Even positions digits = 6, difference $6 - 6 = 0$, divisible by 11.
4. **Summary table with checks:**
| Number | 4 | 8 | 12 | 11 |
|--------|---|---|----|----|
| 88 | ✓ | ✓ | | ✓ |
| 48 | ✓ | ✓ | ✓ | |
| 22 | | | | ✓ |
| 132 | ✓ | | | ✓ |
| 264 | ✓ | ✓ | ✓ | ✓ |
**Final answers:**
- 88 is divisible by 4, 8, and 11.
- 48 is divisible by 4, 8, and 12.
- 22 is divisible by 11 only.
- 132 is divisible by 4 and 11.
- 264 is divisible by 4, 8, 11, and 12.