In math we are working on learning about factors of products (answer to a multiplication problem). For example, the number 15 has four factors: 1, 3, 5, & 15. It's factor pairs are: 1x15, 15x1, 3x5, & 5x3. Since there are four factor pairs, there will be four factors.
Today, we also discussed that if a number has more than two factors, it is a composite number, such as 15. However, if a number ONLY HAS TWO factors, it is prime; such as 7 (1x7 and 7x1 - factors are: 1 and 7).
Check out this fun game to practice your prime and composite numbers, called "Fruit Shoot":
All that said, we are also learning how to tell if a number is divisible by either 1, 2, 3, 5, 6, 9, or 10. The rules are as follows:
- Rule of 1: ALL NUMBERS ARE DIVISIBLE BY 1.
- Rule of 2: Any number which ends in an even number (2, 4, 6, 8, or 0).
- Rule of 3: Add up the digits in the number. If those digits are divisible by 3, the original number is also divisible by 3.
- Rule of 5: Any number which ends with either 0 or 5.
- Rule of 6: If the number is divisible by both 2 and 3, it is also divisible by 6.
- Rule of 9: Add up the digits in the number. If those digits are divisible by 9, the original number is also divisible by 9.
- Rule of 10: Any number which ends with a 0.
To practice these rules, some students made posters to show what they understood. ALL of the posters turned out great! The top poster was voted our class' favorite (also happened to be HUGE).
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