📚 Topic Summary
Divisibility rules are shortcuts to determine if a number can be divided evenly by another number, without actually doing the division. For 2, a number is divisible if its last digit is even (0, 2, 4, 6, or 8). For 5, a number is divisible if its last digit is 0 or 5. For 10, a number is divisible if its last digit is 0. Knowing these rules helps simplify calculations and solve problems faster. These rules work because of the base-ten number system and how remainders work. For example, any number can be written as $10a + b$, where $b$ is the last digit. If you divide that number by $10$, you get $a + \frac{b}{10}$, which means that divisibility depends only on $b$.
🧠 Part A: Vocabulary
Match the term to its definition:
- Term: Divisible
Definition: A number that is divided into another number.
- Term: Remainder
Definition: The amount left over after division.
- Term: Divisor
Definition: Capable of being divided without a remainder.
- Term: Even Number
Definition: An integer that is exactly divisible by 2.
- Term: Multiple
Definition: A number that can be divided by another number without a remainder.
Match the following:
| Term |
Definition |
| 1. Divisible |
A. The amount left over after division. |
| 2. Remainder |
B. Capable of being divided without a remainder. |
| 3. Divisor |
C. A number that is divided into another number. |
| 4. Even Number |
D. An integer that is exactly divisible by 2. |
| 5. Multiple |
E. A number that can be divided by another number without a remainder. |
✍️ Part B: Fill in the Blanks
Complete the sentences using the words: 0, 5, 2, even, 10.
- A number is divisible by _________ if its last digit is _________ or _________.
- A number is divisible by _________ if its last digit is _________.
- A number is divisible by _________ if its last digit is an _________ number.
🤔 Part C: Critical Thinking
Explain why knowing divisibility rules is helpful in everyday life. Give at least two examples.