Show:
Vocabulary
Rounding
Break Apart to Add
Make ten to add
Adding/Subtracting
100

What does it mean to estimate?

To find a number that is close to an exact amount.

100

Round 26 to the nearest ten.

30

100

Solve:

  125
+351
______

100 + 20 + 5
300 + 50 + 1
___________
400 + 70 + 6 = 476

100

Group compatible numbers to add:

  27
  33
+19
_____

79

(check compatible numbers)

100

  356
+523
_____

879

200

What are compatible numbers?

Numbers that are easy to add or subtract mentally

200

Round 321 to the nearest hundred.

300

200

Solve:

  312
+234
______

300 + 10 + 2
200 + 30 + 4
___________
500 + 40 + 6 = 546

200

Group compatible numbers to add:

  16
  25
+34
_____

75

(check compatible numbers)

200

  875
- 231
______

644

300

What is a sum?

The answer to an addition problem.  

300

Round 478 to the nearest hundred.

500

300

Solve:

  348
+206
______

300 + 40 + 8
200 +  0  + 6
____________
500 + 40 + 14 =554

300

Group compatible numbers to add:

  12
  55
+25
_____

92

(check compatible numbers)

300

  900
-323
_____

577

400

Explain what the commutative property of addition is.

The property that states that you can add in any order and still get the same sum.

400

Round 767 to the nearest ten.

770

400

Solve:

  319
+322
_____

300 + 10 + 9
300 + 20 + 2
____________
600 + 30 + 11 =641

400

Mason scored 24 points in a game, Audrey scored 36 and Alaina scored 39 points.  How many points did they score altogether?

99 points

(check compatible numbers)

400

Students at Saranac have a goal of selling 530 items for a fundraiser.  So far they have sold 314 items.  How many more do they need to sell to reach their goal?

216 items

500

Explain what the identity property of addition is.

When the sum of any number added to zero is that same number.

500

Round 479 to the nearest ten

480

500

Break apart to solve:

Lydia collected 143 stickers in first grade and 231 stickers in second grade.  How many stickers did she collect altogether?

100 + 40 + 3
200 + 30 +1
___________
300 + 70 + 4= 374 stickers

500

Jacob collected 27 marbles, Channing collected 23 marbles, and Jayden collected 22 marbles.  How many did they collect altogether?

72 marbles

500

Kaleb won 568 tokens at the arcade.  Zoey won 439 tokens.  How many more tokens did Kaleb win than Zoey?

129 tokens