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.