Estimating Sums and Differences
Addition (with and without regrouping)
Subtraction (with and without borrowing)
Adding and Subtracting Decimal Tenths
Word Problems
100

Estimate the difference 478 - 123 rounding to the nearest ten.

Rounding to the nearest ten: 480 - 120 = 360. 

100

Solve: 25 + 37 =

62

100

Solve: 100 − 37 =

63

100

Solve: 1.2 + 3.7 =

4.9

100

You have 15 pencils in your pencil case. If you give 3 pencils to your friend, how many pencils are left in your pencil case?

Answer: 15−3=1215 - 3 = 1215−3=12
There are 12 pencils left.

200

Estimate 147 + 312 rounding to the nearest ten. 

Rounding to the nearest ten: 150 + 310 = 460. 

200

Solve: 349 + 652 =

1,001

200

Solve: 530 − 215 =

315

200

Solve: 6.8 − 2.5 =

4.3

200

There are 60 books in the library. If 25 books are borrowed by students, how many books are still in the library?

Answer: 60−25=3560 - 25 = 3560−25=35
35 books are still in the library.

300

Estimate the difference of 600 - 275 rounding to the nearest hundred. 

Round both to the nearest hundred: 600 - 300 = 300

300

Solve: 123 + 578 =

701

300

Solve: 650 − 400 =

250

300

Solve: 4.5 + 3.2 =

7.7

300

Emma walks 12 kilometers on Saturday and 8 kilometers on Sunday. How many kilometers does she walk in total over the weekend?

Answer: 12+8=2012 + 8 = 2012+8=20
Emma walks 20 kilometers in total.

400

Estimate 256 + 389 rounding to the nearest hundred. 

Round both to the nearest hundred: 300+400=700

400

Solve: 759 + 184 =

943

400

Solve: 900 − 375 =

525

400

Solve: 5.7 − 1.2 =

4.5

400

A bakery baked 72 cupcakes in the morning. They sold 39 cupcakes by the afternoon. How many cupcakes are left?

Answer: 72−39=3372 - 39 = 3372−39=33
33 cupcakes are left.

500

Estimate the sum of 198 + 462. 

Answer Options:

  • Round both numbers to the nearest hundred: 200+500=700
  • Round 198198198 to the nearest hundred and 462462462 to the nearest fifty: 200+450=650
  • Round both numbers to the nearest ten: 200+460=660
500

Solve: 478 + 265 =

743

500

Solve: 732 − 458 =

274

500

Solve: 3.4 + 2.6 =

6.0

500

Liam has 24 marbles. He buys 16 more and then gives 10 to his friend. How many marbles does Liam have left?

Answer: 24+16−10=3024 + 16 - 10 = 3024+16−10=30
Liam has 30 marbles left.

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