What Does It Mean to Estimate Differences?
Estimating differences is like being a math detective!
Instead of finding the exact answer to a subtraction problem, we make smart guesses by rounding numbers first. This helps us get close to the right answer quickly, which is super useful in real life when you don't need an exact number!
How to Estimate Differences
1️⃣ Round each number to the nearest ten or hundred
2️⃣ Subtract the rounded numbers
3️⃣ Check if your estimate makes sense
Let's Practice Together!
Example 1: Cookie Jar Mystery
Sam's cookie jar had 87 cookies. He ate 32. About how many cookies are left?
Step 1: Round 87 to 90 and 32 to 30
Step 2: 90 - 30 = 60
Step 3: The exact answer is 55, so our estimate of 60 is pretty close!
Example 2: Book Challenge
Emma read 423 pages this month. Last month she read 287 pages. About how many more pages did she read this month?
Step 1: Round 423 to 400 and 287 to 300
Step 2: 400 - 300 = 100
Step 3: The exact answer is 136, so our estimate tells us it's about 100 pages more!
Parent Tips 🌟
- Grocery store practice: When shopping, ask your child to estimate how much change you'll get if you pay with a $20 bill for items totaling $13.47.
- Make it a game: Create "Estimation Challenges" where you both estimate differences and see who gets closer to the actual answer.
- Real-world connections: Point out situations where estimates are useful, like planning time ("If we leave at 3:15 and it takes about 45 minutes...").