Estimating Sums and Differences in Fun Math Challenges

Lily has 25 apples. She gives 7 apples to her friend and then buys 15 more. How many apples does she have now? Estimate the total before calculating.

• 20

• 33

• 25

• 40

Tom has 40 marbles. He loses 12 marbles and then finds 8 more. How many marbles does he have now? Check your answer by estimating first.

• 28

• 32

• 44

• 36

A farmer has 50 chickens. He sells 20 and then buys 10 more. How many chickens does he have now? Estimate the difference and sum.

• 30

• 25

• 40

• 60

Sarah read 15 books in January and 20 books in February. If she gives away 10 books, how many books does she have left? Estimate before solving.

• 30

• 20

• 15

• 25

In a classroom, there are 30 students. If 5 students leave and 10 new students join, how many students are in the classroom now? Check your answer by estimating the changes.

• 25

• 30

• 40

• 35

A toy store had 100 toys. They sold 45 toys and then received a shipment of 30 new toys. How many toys are in the store now? Estimate the total before calculating.

• 100

• 90

• 70

• 85

Mark has 60 stickers. He gives 15 stickers to his sister and then buys 25 more. How many stickers does he have now? Check your answer for accuracy.

• 70

• 80

• 50

• 65

Emma collected 80 seashells. She gave 25 to her friend and found 10 more on the beach. How many seashells does she have now? Estimate the total before calculating.

• 55

• 75

• 85

• 65

A library has 200 books. If 50 books are checked out and 30 new books are added, how many books are in the library now? Check your answer by estimating first.

• 200

• 170

• 150

• 180

Jake has 90 toy cars. He donates 30 cars and then buys 20 more. How many toy cars does he have now? Estimate the difference and sum.

• 60

• 100

• 80

• 70