Breaking Numbers Down
278 + 876
200 + 70 + 8
800 + 70 + 6
1,154
Explain how I would estimate the sum of 124 and 877.
Round 124 --> 120
Round 877 --> 880
Add 880 + 120 = 1,000
Use partial sums to add.
872 + 187
800 + 100 = 900
70 + 80 = 150
7 + 2 = 9
1,059
Break each number down into partial sums and add.
672 + 183 + 19
600 + 100 = 700
70 + 80 + 10 = 160
2 + 3 + 9 = 14
700 + 160 + 14 = 874
Julie is solving this addition problem 124 + 892. She rounds the numbers and says that her estimate is 1,500. Is her estimate reasonable? Why or why not?
No, her estimate is not reasonable. When I round to the tens place I get 120 and 900. 120 + 900 = 1,020. 1,500 is too big to be a reasonable estimate.
Solve. 345 + 283 + 182
810
Use partial differences to subtract.
892 - 341
800 - 300 = 500
90 - 40 = 50
2 - 1 = 1
551
Estimate the difference. 922 - 136
920 - 140 = 780
Solve.
726
382
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332
How can I break apart 198 + 128 by place value?
100 + 100 + 80 + 20 + 8 + 8
326
Estimate the sum of 308 and 182.
Round to the tens place!
310 + 180 = 490
Jamie wants to spend $50 at the store. She grabbed a hat for $32, a scarf for $13, and a pair of sunglasses for $1. How much more can she spend without going over $50?
$4
Which addends are broken apart correctly into hundreds, tens, and ones? Select all that apply.
A. 376+291 --> (300 + 200) + (70 + 90) + (1 + 6)
B. 982+238 --> 980 + 2 + 230 + 8
C. 289+987 --> (200 + 900) + (80 + 80) + (7 + 9)
D. 276+189 --> (200 + 100) + (76 + 89)
A, C
Estimate the sum of 265 and 918, then find the actual answer.
270 + 920 = 1,190
265 + 918 = 1,183
Alexa and her 2 friends are doing a reading contest. In one month, Alexa read 197 hours, June read 245 hours, and Haley read 267 hours. How much did they read all together?
709 hours