Vocabulary
What does it mean to estimate?
To find a number that is close to an exact amount.
Round 26 to the nearest ten.
30
Solve:
125
+351
______
100 + 20 + 5
300 + 50 + 1
___________
400 + 70 + 6 = 476
Group compatible numbers to add:
27
33
+19
_____
79
(check compatible numbers)
356
+523
_____
879
What are compatible numbers?
Numbers that are easy to add or subtract mentally
Round 321 to the nearest hundred.
300
Solve:
312
+234
______
300 + 10 + 2
200 + 30 + 4
___________
500 + 40 + 6 = 546
Group compatible numbers to add:
16
25
+34
_____
75
(check compatible numbers)
875
- 231
______
644
What is a sum?
The answer to an addition problem.
Round 478 to the nearest hundred.
500
Solve:
348
+206
______
300 + 40 + 8
200 + 0 + 6
____________
500 + 40 + 14 =554
Group compatible numbers to add:
12
55
+25
_____
92
(check compatible numbers)
900
-323
_____
577
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.
Round 767 to the nearest ten.
770
Solve:
319
+322
_____
300 + 10 + 9
300 + 20 + 2
____________
600 + 30 + 11 =641
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)
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
Explain what the identity property of addition is.
When the sum of any number added to zero is that same number.
Round 479 to the nearest ten
480
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
Jacob collected 27 marbles, Channing collected 23 marbles, and Jayden collected 22 marbles. How many did they collect altogether?
72 marbles
Kaleb won 568 tokens at the arcade. Zoey won 439 tokens. How many more tokens did Kaleb win than Zoey?
129 tokens