Addition Properties
Mental Math
Rounding Numbers
Adding 2 and 3 Digit Numbers
Problem Solving
100
Fill in the missing number and tell which property of addition is shown. 6+0=?
6 Identity property of addition
100
Use mental math to solve the problem below: 36 + 23 =
59
100
Is the number 27 closer to 20 or to 30? Draw a number line to illustrate your answer.
30 20__________________ 25________27_____________30
100
Use place value drawings to add the following numbers: 58 + 66 =
124 Students must show place value drawings
100
Draw a picture to help solve the problem: A fish tank holds 25 guppies and 18 goldfish. How many fish fit in the tank?
Accept reasonable drawings
200
Is this number sentence true or false? Explain (6+2)+7=8+7
True The sum on each side of the = sign must be the same The Associative Property of Addition states that you can group addends in any way and the sum will be the same.
200
Use mental math to solve this problem: 25 + 14 =
39
200
Round to the nearest 10 156
160
200
First estimate the sum and then find the exact sum: 134 + 156 =
Estimate-300 Exact- 290
200
Draw a bar diagram to help solve this problem: Class 3-BM has 24 students. Class 3-JM has 22 students and Class 3-CP has 26 students. How many students do the three classes have altogether?
24 + 22 + 26 = Bar graph with 3 sections and sum on the top is acceptable
300
What property of addition is shown? 26 + 4 = 4 + 26
Commutative Property of Addition
300
Explain how you can use mental math to add these numbers. 25 + 12 =
First add 20 + 10 = 30 Then add 5 + 2 =7 Finally add 30 + 7 =37
300
Round to the nearest 100 294
300
300
Mrs. Marder ran 18 miles last week. She ran 26 miles this week. She plans to run 28 miles next week. Write a number sentence to show how many miles she has run so far.
18 + 26 =
300
Michael spend $ 27 for tickets to a baseball game and $ 24 on food. About how much money did he spend all together?
$27 + $ 24 = $30 + $ 20 = $50
400
Write a number sentence that shows the Associative Property of Addition.
Responses will vary
400
Use mental math to solve this problem: 72 + 18 =
90
400
What number is half way between 250 and 260?
255
400
Mrs. Marder added 36 + 29 and got 515 as the sum. Explain why this is not a reasonable answer. (Use Writing to Explain format)
First I extimated 40 + 30 and got 70 Then I saw that Mrs. Marder got 515 Finally I realized that 70 is not near 515. This is not a reasonable answer.
500
Give the definition of the: Associative Property Identity Property Commutative Property
Associative Property-You can group addends in any way and the sum will be the same. Identity Property- The sum of 0 and any number is always that number. Commutative Property-You can add numbers in any order and the sum will be the same.
500
Use mental math to find the sum: 34 + 25 = Explain how use found the sum.
59 Answers can vary
500
Writing to Explain: Use the format we learned in class to explain: How would you round 46 to the nearest 10.
First I would underline the 4 Then I would look at the digit to the left. 6 is greater than 5 so I would increase the tens digit one and change it to a 5. The ones digit changes to a 0. Finally I round 46 to 50
500
Use estimation to find out about how many apples class 3-BM picked on their field trip. 29 + 33 + 14 =
30 + 30 + 10 = 70
500
Which stategy would be appropriate to use if your problem has more than one answer?
An Organized List
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