What Are Subtraction & Multiplication Patterns?
Patterns make math exciting and predictable!
When we combine subtraction and multiplication, we can create fascinating number sequences. These patterns help us predict what comes next and understand how numbers relate to each other.
How to Find These Patterns
1️⃣ Look at the sequence of numbers carefully
2️⃣ Try subtracting one number from the next
3️⃣ Check if multiplying gives you a pattern
4️⃣ Combine both operations to find the rule
Let's Explore Some Examples!
Example 1: The Shrinking Stars
Look at this pattern: 100, 90, 81, 72, 64, 56, 49, ...
Can you figure out the rule?
Here's the magic rule: Subtract 10, then subtract 9, then subtract 8, and so on!
100 - 10 = 90
90 - 9 = 81
81 - 8 = 73 (Wait, that doesn't match! Hmm...)
Actually, there's another pattern: Subtract 10, then subtract 9, then subtract 9, then subtract 8, then subtract 8, then subtract 7...
Or even better: Multiply by 0.9 (90%) each time! Isn't that cool?
Example 2: Cookie Sharing Pattern
Imagine you have 120 cookies to share with friends. Each day you:
1. Multiply the cookies by \(\frac{3}{4}\) (keep 3/4 of them)
2. Then subtract 5 cookies to give to your teacher
What happens after 3 days? Try calculating!
Day 1: (120 × ¾) - 5 = 90 - 5 = 85 cookies
Day 2: (85 × ¾) - 5 ≈ 63 - 5 = 58 cookies
Day 3: (58 × ¾) - 5 ≈ 43 - 5 = 38 cookies
See how combining multiplication and subtraction creates this shrinking pattern?
Parent Tips 🌟
- Make it visual: Use coins, blocks, or candies to physically demonstrate the patterns - kids learn better when they can touch and move objects!
- Connect to real life: Show how these patterns appear in shopping discounts ("30% off, then $5 coupon") or video game power-ups.
- Celebrate mistakes: When patterns don't work as expected, it's a great opportunity to explore why and discover deeper math concepts.