Vocabulary
A number close to an exact number
Estimation or Estimate
Which addition property states that if you add 0 to a number, the sum is the same as the give number?
Identity Property of Addition
Which mental math strategy is this an example of?
12 + 17 =
-3 +3
9 + 20 =
Making tens
Estimate the sum by rounding addends to the nearest 10.
78
+57
80 + 60 = 140
Solve for the unknown.
345 + 562 = ?
907
Within the bounds of making sense
Reasonable
Solve the problem and write which property of addition is represented by number sentences below?
(9 + 4) + 6 =
(6 + 4) + 9 =
19; Associative Property of Addition
Which mental math strategy is represented by the problem below?
726 = 700 + 20 + 6
+92 = + 90 + 2
Expand and Add
Estimate the sum by rounding addends to the nearest 100.
537 + 281 =
500 + 300 = 800
2,508 + 489 = ?
2,997
A missing number or the number to be solved for.
The unknown
Which property of addition is states that the order in which two numbers are added does not change the sum?
Commutative Property of Addition
Use the base ten system to show and answer this addition problem:
217 + 144 =
## l ....... + # llll .... =
### llllll .
Solve the following equation and check for reasonableness.
173 + 404 =
577; estimations will vary (examples: 170 + 400 = 570, 200 + 400 = 600)
Peter bakes 822 chocolate chip cookies for a charity bake sale. Rachel bakes 347 snickerdoodles for the bake sale. How many cookies did they bake in all?
1,169 cookies
Ordering or grouping numbers so they are easier to add in your head.
Mental Math
Write an equation that represents the Commutative Property of Addition
Answers will vary
Use a mental math strategy to find the answer to the following problem. Show your work and write which strategy you used.
94 + 58 =
152; answers vary
Solve the following equation and check for reasonableness.
5,706 + 1,269 =
6,975; estimations will vary (examples:
5,710 + 1,270 = 6,980
5,700 + 1,300 = 7,000
6,000 + 1,000 = 7,000)
3,255 + 2,916
6,171
A tool/visual used to illustrate number relationships.
Bar diagram
Write an equation that represents the Associative Property of Addition.
Answers will vary.
Use a mental math strategy to find the answer to the following problem. Show your work and write which strategy you used.
711 + 284 =
995; answers will vary
Marci goes to the store to buy birthday presents for her twin brothers. She knows that one brother wants a skateboard that costs $28. The other brother wants a robotics kit that costs $32. She also wants to buy both brothers a box of chocolates that cost $7 each.
About how much money will Marci spend on her brothers?
30 + 30 + 10 +10 = 80; About $80
First grade and third grade at Ashbrook School both use class dojo. At the end of the year, first grade has a total of 4,394 dojo points and third grade has earned 7,641 dojo points. How many points did they earn all together?
They earned 12,035 dojo points