Adding
What is the sum of 243, 132, and 157?
532
If you subtract 382 - 148, which of the following would be the first step that you do?
A. Add 2 to 148 and add 2 to 282
B. Add 2 to 148, and subtract 2 from 282
C. Subtract 8 from 148, and subtract 2 from 382
D. Subtract 12 from 382, and add 12 to 148
A. If you add the same amount to both sides you can subtract and get the same difference
If I am subtracting 341-97 mentally, I will add 3 to 97 to get to 100. What would my next step be?
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. What you add to one side, you HAVE to add to the other.
Look at the equation 171 + 69. Is the following a reasonable estimate? Why or why not?
100 + 60
No, 100 is too far off from 171. 171 is closer to 200
Estimate the difference between 765 and 333 explain your reasoning.
Use mental math to add 332 + 154. Which of the following is the correct way to break it apart.
A. break 332 into 320 + 12. Break apart 154 into 125 +9
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 apart 154 into 100 +50 +2
D. Break each number apart by using place value.
use mental math to solve 634-528
106
Look at the equation 360 = ___ + 84. Create a bar diagram to represent the equation. Solve for the unknown value.
360 - 84 = 276
Estimate the sum of 405 and 385 by rounding to the nearest hundred.
400 + 400 = 800
Use compatible numbers to add 123, 201, and 387
A. Is this equation true or false? Explain
32 + 56 + 10 = 10 + 56 + 32
B. Is this equation true or false? Explain
(49 + 28) + 5 = 49 + (28 +5)
Yes, it is using the commutative property.
Yes, it is using the associative property.
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.
342 + 114 = 456
Billy's office building has 126 windows. Morgan's bank has 146 windows. Devon's bank has 110 windows. How many more windows do the banks have altogether than the office building?
The banks have 130 more windows than the office building
Round 668 to the nearest hundred
700
Use compatible numbers to estimate 760 - 265
Find the sum of 350, 62, and 199 draw a bar diagram to represent the problem.
611
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
D
Anna and Joe write reports for their science class. Anna's report is 827 words long. Joe's report is 679 words long. Round each report length to the nearest ten and estimate how many more words Anna's report it, then figure out exactly how many more words Anna's report is.
estimate: 830 - 680 = 150
exact: 148
Round 404 to the nearest hundred
400
481-105
674 + 112 + 42
727
845- 348
497
Sara collected 220 cans on Monday. 80 cans on Tuesday, and 7 cartons with 8 cans each on Wednesday to recycle. Pierre collected 112 cans. About how many more cans did Sara collect than Pierre?
220 + 80 +60 = 360
360 -112 =248
Estimate the sum of 123, 201, and 387 rounded to the nearest ten.
120 + 200 + 390 =710
355-177