Number Model Estimates
Partial Products/Standard Method
Adding or Subtracting Decimals
Word Problems
Analyzing Data and powers of 10
100
Circle the number closest to the sum. Write the number model for the estimate: 219+271 600 500 400 300
200+300=500
100
Multiply. Use the partial-products algorithm. Show your work. 27*6
20*6 = 120 7*6 = 42 =162
100
Add or Subtract. Show your work. 1.9+12.1=
1.9+12.1=14
100
Mrs. Marchesi sleeps and average of 7 hours a day. How many hours does Mrs. Marchesi sleep during a 2-week period? Estimate if the answer will be in the 10s 100s 1,000s or 10,000s. Then right the number model estimate and solve for the exact answer.
estimate: 100s number model: 10*10=100 exact: 7*14=98
100
On average, 7,000 elephants are born on earth every day. How many elephants are born in a week?
7*7,000= 49,000 elephants
200
Circle the number closest to the sum. Write the number model for the estimate: 412+307 900 800 700 500
400+300=700
200
Multiply. Use the partial-products algorithm. Show your work. 33*3
30*3= 90 3*3=9 =99
200
Add or Subtract. Show your work. 8.3-5.7=
8.3-5.7=2.6
200
There is an average of 25 students in each classroom at Shady Groves. If there are 32 classrooms in the school, then how many students attend Shady Grove? Estimate if the answer will be in the 10s 100s 1,000s or 10,000s. Then right the number model estimate and solve for the exact answer.
estimate:100s number model: 30*30= 900 exact: 25*32=800
200
On average, 10,000 people are born on earth every day. What is that with an exponent?
10 to the 4th power
300
Circle the number closest to the sum. Write the number model for the estimate: 697+503 1,200 1,100 1,300 1,000
700+500=1,200
300
Multiply. Use the partial-products algorithm. Show your work. 49*16
40*10 = 400 40*6=240 9*10 = 90 9*6=54 =784
300
Add or Subtract. Show your work. 17.3-9.56=
17.3-9.56=7.74
300
If there are an everage of 734 students in each elementary school and there are 9 elementary schools, then how many elementary school students go to the 9 schools in all? Estimate if the answer will be in the 10s 100s 1,000s or 10,000s. Then right the number model estimate and solve for the exact answer.
estimate: 1,000s number model: 700*10=7000 exact: 734*9= 6,606
300
On average, 7,000 elephants are born on earth every day. How many elephants would be born in the month of January alone?
31*7,000= 217,000 elephants
400
Circle the number closest to the sum. Write the number model for the estimate: 331+197+218 800 900 700 600
300+200+200=700
400
Multiply. Use the standard method. Show your work. 67*45
=3,015
400
Add or Subtract. Show your work. 23.652+21.83=
23.652+21.83=45.482
400
Every student in Mrs. Marchesi's 4th grade classroom must read at least 400 pages in order to win the "Golden Book." There are 25 students in the classroom. How many pages will the entire class need to read? Estimate if the answer will be in the 10s 100s 1,000s or 10,000s. Then right the number model estimate and solve for the exact answer.
estimate:10,000s number model: 400*30=12,000 exact: 400*25 = 10,000
400
On average, just under 10 billion chickens are born on earth every year. What is that with an exponent?
10 to the 10th power
500
Circle the number closest to the sum. Write the number model for the estimate: 624+709+351 1,700 1,600 2,000 1,650
600+700+400=1,700
500
Multiply. Use the standard method. Show your work. 143*15
=2,145
500
Add or Subtract. Show your work. 41.1-8.936=
41.1-8.936=32.164
500
Mrs. Marchesi drives a total of 31 miles each school day. How many miles does Mrs. Marchesi drive during a 3-week period? Estimate if the answer will be in the 10s 100s 1,000s or 10,000s. Then right the number model estimate and solve for the exact answer.
estimate: 100s number model: 30*20 = 600 exact: 15*31=465
500
Mrs. M completes the following math problem but makes a MISTAKE... What did she do wrong? Then, calculate the correct answer: 743.26 - 35.4 --------------- 739.72
Mrs. M did not lign up her place values! The correct answer is 707.86
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