Estimating Numbers Worksheet

**Page 1**

1.

A pair of jeans is on sale for $22. The original price was $47. Which is the best estimate of the discount?

a. | $\frac{1}{3}$ | ||

b. | $\frac{1}{5}$ | ||

c. | $\frac{1}{4}$ | ||

d. | $\frac{1}{2}$ |

Correct answer : (4)

2.

Estimate the sum of 663 and 353, using front-end estimation.

a. | 1010 | ||

b. | 900 | ||

c. | 955 | ||

d. | 1020 |

663 + 353 is about 665 + 355

= 600 + 65 + 300 + 55

= 1020

Correct answer : (4)

3.

Estimate the sum of 1384 and 363.

a. | 1750 | ||

b. | 1600 | ||

c. | 1700 | ||

d. | 1685 |

[85 + 65 = 150.]

1384 + 363 is about 1385 + 365

= 1300 + 85 + 300 + 65

= 1750

Correct answer : (1)

4.

Jacques has saved $635. If he wants to save $1,000, estimate how much more he still has to save.

a. | $300 | ||

b. | $400 | ||

c. | $1,635 | ||

d. | $65 |

He saved $635

So, the more money still he has to save = $1,000 - $600 = $400.

Correct answer : (2)

5.

Lehman puts oranges in cartons in his shop. He puts 43 to 49 oranges in each carton. Which could be the total number of oranges he puts in 10 cartons?

a. | Between 400 and 500 | ||

b. | Between 200 and 300 | ||

c. | Less than 200 | ||

d. | More than 500 |

He puts a maximum of 49 oranges in each carton and its nearest value to tens is 50.

In 10 cartons, the minimum number of oranges kept by Lehman is 40 * 10 = 400.

In 10 cartons, the maximum number of oranges kept by Lehman is 50 * 10 = 500.

Therefore,

Correct answer : (1)

6.

During the past 8 weeks, Anna spent between $22 and $38 for magazines each week. Which could be the total amount that he spent on the magazines for the past 8 weeks?

a. | Less than $160 | ||

b. | Between $20 and $40 | ||

c. | Between $160 and $360 | ||

d. | Between $240 and $320 |

Maximum amount spent by her is $38 and its nearest value to tens is $40.

For 8 weeks, Anna's minimum expenses are $20 * 8 = $160.

For 8 weeks, Anna's maximum expenses are $40 * 8 = $320.

Therefore, among the choices, between $160 and $360 is correct.

Correct answer : (3)

7.

During the past 10 weeks, Jerry spent between $3547 and $5285 for business trips each week. Which could be the total amount that he spent on the trips for the past 10 weeks?

a. | Between $4000 and $5000 | ||

b. | Between $35,000 and $53,000 | ||

c. | Between $30,000 and $50,000 | ||

d. | Less than $30,000 |

Maximum amount spent by him is $5285 and its nearest value to hundred is $5,300.

For 10 weeks, Jerry's minimum expenses are $3500 * 10 = $35,000.

For 10 weeks, Jerry's maximum expenses are $5300 * 10 = $53,000.

Therefore,

Correct answer : (2)

8.

Amy has collected 831 marbles. If she wants to collect 1,000 marbles, estimate how many more marbles she needs to collect.

a. | 200 | ||

b. | 100 | ||

c. | 70 | ||

d. | 300 |

She wants to collect 1,000 marbles.

So, the number of marbles she needs to collect = 1,000 - 800 = 200.

Correct answer : (1)

9.

Eric wants to go to his Aunt's house which is located 1,000 km away from his house. Estimate the distance Eric has to cover, if he already had traveled 560 km.

a. | 300 km | ||

b. | 500 km | ||

c. | 400 km | ||

d. | 700 km |

He already covered 560 km

So, the distance he has to cover = 1,000 - 600 = 400 km.

Correct answer : (3)

10.

Lisa wants to buy a doll which costs $1,000. If she has $890, estimate the amount she still needs to buy the doll.

a. | $50 | ||

b. | $200 | ||

c. | $70 | ||

d. | $100 |

Lisa has $890

So, Lisa still needs = $1,000 - $900 = $100.

Correct answer : (4)