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Addition
Subtraction
Vocabulary Words
Estimation
Word Problems
Rounding
Different ways to write numbers
100
43.45 + 0.90 + 56 =
100.35
100
12.99 - 3.95 =
9.04
100
10 * 10 * 10 * 10 are called
Repeated Factors
100
Estimate the sum. 79.1 + 34.5 =
Sample Answers: 80 + 35 = 115 80 + 34 = 114
100
How is adding 45.8 + 67.8 similar to adding 67.8 + 45.8?
They used the Commutative Property of Addition to change the order of the numbers being added but the sum remains the same.
100

What is 4.567 rounded to the nearest hundredth?

4.57

100

Write 895.23 in expanded form.

(8 x 100) + (9 x10) + (5 x 1) + (2 x 1/10) + (3 x 1/100)

200
1.35 + 3 + 4.45 + 0.65
9.45
200
87.06 - 45.92 =
41.14
200
Numbers that are easy to compute with mentally
Compatible Numbers
200
Estimate the difference. 418.5 - 23.7 =
Sample Answers: 400 - 20 = 380 420 - 20 = 400
200
Three pieces of software cost $56.88, $34.89 and $134.90. What is the total cost of the software?
The total cost is $226.67.
200

What is 10.589 rounded to the nearest tenths?

10.6

200

Write (7 x 100) + (3 x 1) + (4 x 1/100) in standard form.

703.04

300
209.8 + 896.54
1,106.34
300
788.2 - 532 =
256.2
300
Adjusting one number to make a computation easier and balancing the adjustment by changing another number
Compensation
300
Estimate the difference. 23.8 + 34.1 + 3.3 =
Sample Answers: 25 + 35 + 5 = 65 20 + 30 + 3 = 53 20 + 35 + 5 = 60
300
In a week, Beth ran 9.7 miles and Jess ran 5.3 mile. About how many miles did they run in all?
They ran about 15 miles.
300

What is 134.23 rounded to the nearest whole number?

134

300

Write 145.06 in number name.

one hundred forty-five and six hundredths

400
985 + 678.54
1,663.54
400
76.7 - 34.26 =
42.44
400
The ______________________ states that the addends can be added in any order and the sum remains the same.
Commutative Property of Addition
400
Estimate the difference. 87.7 - 18 =
Sample Answers: 90 - 20 = 70 87 - 17 = 60
400
Danny put two entertainment units together for his two big screen televisions. The Oak was 8.45 feet tall and the Birch was 7.23 feel tall. What is the combined height of the two entertainment units? How much taller is the Oak than the Birch?
The total is 15.68 feet. The Oak is 1.22 feet taller.
400

What is 9.981 rounded to the nearest tenth?

10

400

Write 7,219.3 in expanded form.

(7 x 1000) + (2 x 100) + (1 x 10) + (9 x 1) + (3 x 1/10)

500
388.76 + 45 + 267.96 =
701.72
500
1,256.12 - 987.76 =
268.36
500
The ________________ states that the addends can be regrouped and the sum remains the same.
Associative Property of Addition
500
Estimate the sum. 576 + 345.9 + 999 =
Sample Answers: 600 + 350 + 1000 = 1950 600 + 300 + 1000 = 1900
500
Two rock samples have masses of 56.24 grams and 8.98 grams. Which of the following is the best estimate of the total mass of the rock samples? 56 grams, 63 grams, 65 grams, or 70 grams (HINT: Round to the nearest whole.)
65 grams
500

What is 137.8923 rounded to the nearest thousandth?

137.892

500

Write 6,034.321 in number name.

six thousand thirty four and three hundred twenty one thousandths