Practice the problems of Math in Focus Grade 2 Workbook Answer Key Chapter 10 Practice 5 Rounding Numbers to Estimate to score better marks in the exam.

## Math in Focus Grade 2 Chapter 10 Practice 5 Answer Key Rounding Numbers to Estimate

**Mark each number with an ✗ on the number line.**

**Round each number to the nearest ten. Circle it on the number line. Then fill in the blanks.**

Example

Question 1.

48 is nearer to __ than to ____

48 is about ___ when rounded to the nearest ten

Answer:

48 is nearer to 50 than to 40

48 is about 50 when rounded to the nearest ten

Question 2.

35 is about ________ when rounded to the nearest ten.

Answer:

35 is about 40 when rounded to the nearest ten.

Question 3.

26 is nearer to _________ than to ___.

26 is about ________ when rounded to the nearest ten.

Answer:

26 is nearer to 30 than to 20.

26 is about 30 when rounded to the nearest ten.

**Look at the digits in the tens place. Then till in the blanks.**

Example

37 is between __30__ and __40__

Question 4.

86 is between _________ and ____

Answer:

86 is between 80 and 90

Question 5.

93 is between _________ and ____.

Answer:

93 is between 90 and 100.

Question 6.

286 is between _______ and ____

Answer:

286 is between 280 and 290

Question 7.

721 is between ________ and ________

Answer:

721 is between 720 and 730

**Mark each number with an ✗ on the number line. Round each number to the nearest ten. Circle the number on the number line. Then fill in the last column of the table.**

Question 8.

Answer:

Question 9.

Answer:

Question 10.

Answer:

**Complete the table.**

Question 11.

Answer:

Question 12.

Answer:

Question 13.

Answer:

Question 14.

Answer:

Question 15.

Answer:

**The numbers in each problem are rounded to the nearest ten. Find the greatest and least number that is rounded. Use the number line to help you.**

Example

Mr. Johnson spent about $80 at a department store.

The greatest amount he could have spent is $__84__.

The least amount he could have spent is $ __75__.

Question 16.

Charles drinks about 790 milliliters of fruit juice in one day.

The greatest amount he could have had is _________ milliliters.

The least amount he could have had is _________ milliliters.

Answer:

The greatest amount he could have had is 794 milliliters.

The least amount he could have had is 785 milliliters.

Question 17.

Shateel ran about 750 meters.

The greatest distance she could have run is _________ meters.

The least distance she could have run ¡s _________ meters.

Answer:

The greatest distance she could have run is 754 meters.

The least distance she could have run ¡s 745 meters.

Question 18.

The mass of a bag of potatoes ¡s about 830 grams.

The greatest mass of the potatoes could be ___ grams.

The least mass of the potatoes could be ___ grams.

Answer:

The greatest mass of the potatoes could be 834 grams.

The least mass of the potatoes could be 825 grams.

**Find the sum or difference. Then round each number to the nearest ten. Estimate the sum or difference to check that the answers are reasonable.**

Example

763 + 36 = 799

763 is about __760__

36 is about __40__

760 + 40 = __800__

So, 763 + 36 is about __800__

Is the answer reasonable?

Explain. __Yes, because 800 is close to 799.__

Answer:

Question 19.

238 + 98 = _______

238 is about _____

98 is about ____.

___ + ____ = ____

So, 238 + 98 is about ____

Is the answer reasonable? Explain. _____

Answer:

238 + 98 = 336

238 is about 230

98 is about 100.

230 + 100 = 330

So, 238 + 98 is about 330

Explanation : No, As 330 is the nearest tenth value of 336

Question 20.

847 – 95 = _______

847 is about ____.

95 is about ____.

_____ – ____ = _____

So, 846 – 95 = ____

____ – ____ = ____

Is the answer reasonable? Explain. _______

Answer:

847 – 95 = 752

847 is about 840.

95 is about 90.

840 – 90 = 750

So, 846 – 95 is about 330

847 – 95 = 752

Explanation: __Yes, because 750 is close to 752__

Question 21.

781 + 49 = _______

Check: _________ + _________ = _____.

Is the answer reasonable? Explain.

Answer:

781 + 49 = 830

781 is about 780.

49 is about 50.

780 + 50 = 830

Check: 781 + 49 = 830

Explanation: __Yes, because 830 is equal to 830__

Question 22.

259 – 72 = _______

Check: ________ – ________ = ____.

Is the answer reasonable? Explain.

Answer:

259 – 72 =187

260 is about 260.

72 is about 70.

260 – 70 = 190

Check: 259 – 72 is about 187

Explanation: __Yes, because 190 is close to 187__

Question 23.

The school principal has $900 to buy items for the school. Round the cost of each item to the nearest ten.

Then estimate the total cost.

a. A set of 4 textbooks costs $96.

96 is _________ when rounded to the nearest ten.

Answer:

96 is 100 when rounded to the nearest ten.

b. A printer costs $215.

215 is _________ when rounded to the nearest ten.

Answer:

215 is 210 when rounded to the nearest ten.

c. A camera costs $147.

147 is _________ when rounded to the nearest ten.

Answer:

147 is 150 when rounded to the nearest ten.

d. A computer costs $385.

385 is _________ when rounded to the nearest ten.

Answer:

385 is 380 when rounded to the nearest ten.

e. The estimated total cost is $ ___.

Answer:

We have the rounded values as given below

A set of 4 textbooks costs = $100

A printer costs = $210

A camera costs = $150

A computer costs = $380

we get the cost by adding all the above mentioned values.

that is

$100 + $210 + $150 + $380 = $840

total cost is $840

f. Does the principal have enough money to pay for all the items?

__________

Answer: Yes, The principal have enough money to pay for all the items.