We love Zeros!
Estimate
Break Apart Strategy
Reasonableness
100
9 X 10
What is 90?
100
Estimate? 32 X 8
What is 240?
100

Use Break Apart to Solve:


27 x 9

243

100

Ursula has an album in which she keeps pressed flowers. The album has 34 pages, and each page has 7 pressed flowers. Which of the following shows a reasonable estimate of how many pressed flowers Ursula has

A     30 × 7 = 210

B     40 × 7 = 280

C     50 × 5 = 250

D     60 × 4 = 240

A     30 × 7 = 210

200
7 X 100
What is 700?
200

Estimate: 832 X 9

What is 7,200

200

Use Break Apart Strategy to Solve:


83 x 9 

747

200

Isabelle has 9 ant farms. Each ant farm has 99 ants. Which of the following shows a reasonable estimate of how many ants Isabelle has?

A     7 × 125 = 875

B     8 × 110 = 880

C     9 × 100 = 900

D     10 × 100 = 1,000

C     9 × 100 = 900

300
6 X 700
What is 4,200?
300

Estimate: 166 X 6

What is 1,200?

300

Use Break Apart to Solve:


347 x 9

3,123

300

At an athletic club there are 11 people on a sports team. There are 8 teams. About how many people are on teams?

80 people

400
475 X 1,000
What is 475,000?
400

Estimate: 523 X 4

What is 2,000?

400

Use Break Apart Strategy to Solve:


938 x 6 

5,628

400

 Kenny has 7 pouches. Each pouch has 21 marbles. About how many marbles does Kenny have?

140 marbles

500
3 X 2,500
What is 7,500?
500

Estimate 5,000 X 7 

What is 35,000?

500

Use Break Apart Strategy to Solve: 


648 x 7

4,536

500

Every day for 1 week Derek’s cousin told him 11 jokes. Each joke took 3 minutes to tell. Derek thinks his cousin told him 33 minutes of jokes in the 1 week. Explain why this answer is not reasonable. 

This answer is not reasonable because Derek's cousin told 11 jokes each day for a week. That means he told 77 jokes in 1 week. If each joke took him 3 minutes to tell, you would need to do 77 x 3 to find the answer, which is 231 minutes. Much higher than 33 minutes. 

M
e
n
u