Estimating Sums & Differences in 3-Digit Math Fun!

1. Sarah has 245 marbles, and she buys 378 more. How many marbles does she have now? Estimate the total before calculating.

• 700

• 600

• 623

• 500

2. A library has 512 books. If 129 books are checked out, how many books are left in the library? Use a number line to help visualize the subtraction.

• 400

• 450

• 383

• 350

3. Tom collected 456 stickers, and he gave 123 to his friend. How many stickers does Tom have left? Estimate the difference first.

• 400

• 333

• 350

• 250

4. A toy store sold 678 toys in January and 245 toys in February. How many toys did they sell in total? Estimate the sum before finding the exact number.

• 600

• 800

• 950

• 923

5. There are 834 students in a school. If 215 students are absent, how many students are present? Use a number line to assist with the subtraction.

• 619

• 700

• 800

• 600

6. Emma read 256 pages of a book and plans to read 145 more pages. How many pages will she have read in total? Estimate the total pages read.

• 400 pages

• 450 pages

• 401 pages

• 300 pages

7. A farmer has 789 apples and sells 432 apples at the market. How many apples does he have left? Estimate the difference before calculating.

• 357

• 200

• 789

• 432

8. A concert had 345 tickets sold on Friday and 678 tickets sold on Saturday. How many tickets were sold over the two days? Estimate the total first.

• 1100

• 1023

• 1000

• 900

9. A baker made 512 cookies and sold 289 of them. How many cookies does the baker have left? Use a number line to visualize the subtraction.

• 300

• 223

• 200

• 250

10. In a classroom, there are 423 pencils. If 198 pencils are broken, how many pencils remain? Estimate the difference before calculating the exact number.

• 300

• 225

• 200

• 250