Pigs
Horses
Cows
Chickens
Goats
100
1.What is the sum of 243, 132, and 157?
532
100
4. Estimate the difference of 765 and 333. Explain your estimate.
770-330 = 440; I rounded to the nearest 10.
100
11. Estimate the sum of 405 and 385 by rounding to the nearest hundred. Explain your estimate.
400+400 = 800
100
16. Explain how to use mental math to find 620 - 278.
Sample: 620 - 200 = 420
420-20 = 400-50 = 350 - 8 = 342
100
Which property of addition is shown in the following example:
17 + 14 = 14 + 17
Commutative Property of Addition
200
12.What addition equation can be used to check the answer for
456-342 =114
Draw a bar diagram to show how the numbers in this problem are related.
114 + 342 = 456
Check students' bar diagram
200
7.Use mental math to find 634 -528.
Example: 528 +6 = 530
634-534 = 100+100+6 = 106
200
2. Find a reasonable estimate for the sum of 171 and 69. Select all that apply.
A. 175 + 70 = 245
B. 100 + 60 = 160
C. 170 + 70 = 240
D. 175 + 75 = 250
E. 130 + 70 = 200
A,C,D
200
Addition and subtraction are ___________ operations.
inverse/opposite
200
Numbers that are easy to compute mentally are _______________. (They end in 0 or 5)
compatible numbers
300
19.Consider the equation 360 = ------ + 84
Use a bar diagram to represent the equation. Then solve for the unknown value.
Check bar diagram. 276
300
(10 + 9) + 8 = ? + (9 + 8). You use the _____________Property because:
Associative b/c the grouping order will not change the sum, so you have to balance the equation.
300
5. (P. 327) Look at the sums in the shaded column. Look at the addends. What pattern do you see?Explain why this pattern.
The sum is always the same as one of the addends b/c of the Identity Property of Addition.
300
3. Subtract 382-148 mentally. Which of the following should you do first to find the difference?
𝖠. Add 2 to 148 and add 2 to 382.
𝖡. Add 2 to 148 and subtract 2 from 382.
𝖢. Subtract 8 from 148 and subtract 2 from 382.
𝖣. Subtract 12 from 382 and add 12 to 148.
A.
300
17.How can you check the answer for 693 - 231 = 462.
A. Subtract 639 - 300 = 339
B. Subtract 462 - 231 = 231
C. Add 693 + 231 = 924
D. Add 462 + 231 = 693
D
400
15. Round each number on the left to the nearest hundred. Select the appropriate answer.
400
6. Use mental math to add 332 and 154. Which of these shows how to break apart the numbers into hundreds, tens,and ones?
𝖠. Break 332 into 320 + 12. Break 154 into 125 + 29.
𝖡. Break 332 into 100+230+2. Break 154 into 100+52+2.
𝖢. Break 332 into 300+16+16. Break 154 into 100+27+27.
𝖣. Break 332 into 300+30+2. Break 154 into 100+50+4.
D.
400
What are the next three letters in this pattern?
ABC XYZ DEF UVW GHI
RST
400
8.Select all the equations that are true.
A. 32 + 56 +10 = 10 + 56 +32
B. (49+28) +5 = 49 + (28+5)
C. 56 + 890 = 890 + 56
D. 82 + 0 = 82
E. 45 + 27 = 27 + 35
A, B, C, D
400
10.Use the subtraction work shown.
Which strategy shows a way to check the work using inverse operations?
𝖠. Subtract 57 from 169.
𝖡. Add 57 and 112.
𝖢. Add 112 and 169.
𝖣. Add 169 and 57.
B
500
9.Look at the table. (328)
A. 168
B. 153
C. 161
D. 179
Write the letters A, B, C, and D above the number line to show each number rounded to the nearest ten.
Check student number lines.
500
13. Find the sum of 350, 62, and 199.
A. Draw a bar diagram that represents the problem.
B.What is the first step you would do to solve this problem using mental math?
A. Check bar diagrams
B. Sample: 350 + 200 = 550 + 50 + 11 = 611
500
In the following message, the numbers 1–26 have been substitutedfor the letters A–Z (for example, 1 = A, 2 = B, and so on).What does the 4-word message say?
9 12-15-22-5 19-5-3-18-5-20 3-15-4-5-19!
I LOVE SECRET CODES!
500
18. Consider the sum of 123, 201, and 387.
A. Estimate the sum by rounding to the nearest ten. Explain your estimate.
B. What is the difference between the exact sum of 123, 201, and 387 and your estimate? Explain your answer.
Part A:
123 = 120
201 = 200
387 = 390
120+200+390 = 710
Part B:
123+201+387 = 711, So, 1.
500
14. Subtract 341 - 97 mentally. First add 3 to 97 to get 100. What should the next step be? What is the difference?
𝖠. Add 6 to 341. The difference is 247.
𝖡. Add 200 to 100. The difference is 100.
𝖢. Subtract 3 from 341. The difference is 238.
𝖣. Add 3 to 341. The difference is 244.
D