All the solutions provided in McGraw Hill Math Grade 3 Answer Key PDF Chapter 3 Lesson 3 Problem-Solving Investigation: Estimator Exact Answer will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 3 Answer Key Chapter 3 Lesson 3 Problem-Solving Investigation: Estimator Exact Answer
Learn the Strategy
To celebrate Arbor Day, Brita’s school district planted trees. The high school students planted 1,536 trees. The elementary students planted 1,380 trees. About how many more trees did the high school students plant?
1. Understand
What facts do you know?
The high school students planted ____ trees.
The elementary students planted ____ trees.
Answer:
The high school students planted 1,536 trees.
The elementary students planted 1,380 trees.
What do you need to find?
about how many more trees the ___ students planted
2. Plan
Answer:
The high number of students planted 156 trees.
Explanation:
About how many more trees the high students planted is 1,536-1,380 which is 156 trees.
An exact answer is not needed. I will estimate
3. Solve
About 100 more trees were planted by the high school students.
4. Check
Does your answer make sense? Explain.
Answer:
Yes, the answer makes sense.
Explanation:
Yes, the answer makes sense. As we have solved in question 3 and the estimation is closer to the answer.
Practice the Strategy
Students in grades 2 and 3 wrote 61 stories to celebrate author day. The second graders wrote 26 stories. How many stories did the third graders write?
1. Understand
What facts do you know?
____________________
____________________
Answer:
The facts we know are, that a number of stories were written by 2nd and 3rd-grade students.
What do you need to find?
____________________
Answer:
We need to find the number of stories did the third graders write.
2. Plan
____________________
____________________
Answer:
We will subtract from the 26 from 61 to get the number of stories did the third graders write.
3. Solve
Answer:
By subtracting 61-26 we will get 35 stories written by the third graders.
4. Check
Answer:
To check we will add 26 and 35 which is 26+35= 61.
Does your answer make sense? Explain.
Yes, the answer makes sense. As we have cross-checked the above answer.
Apply the Strategy
Determine whether each problem requires an estimate or an exact answer. Then solve.
Question 1.
Mathematical PRACTICE 4 Model Math Michelann cut two lengths of rope. One was 32 inches long. The other was 49 inches long. Will she have enough rope for a project that needs 76 inches of rope? Explain.
Answer:
Yes, Michelann will have enough rope for the project.
Explanation:
Given that Michelann cut two lengths of rope. One was 32 inches long and the other was 49 inches long. So we need to check that will she have enough rope for a project that needs 76 inches of rope. The length of the two ropes is 32+49 which is 81 inches. So Michelann will have enough rope for the project as she needs 76 inches only.
Question 2.
Mathematical PRACTICE 2 Use Number Sense The number 7 septillion has 24 zeros after it. The number 7 octillion has 27 zeros after it. How many zeros is that altogether? What is the difference between the number of zeros in 7 septillion and 7 thousand?
Answer:
The number of zeros altogether is 51 zeros and the difference between the number of zeros in 7 septillions and 7 thousand is 21 zeros.
Explanation:
Given that the number 7 septillion has 24 zeros after it and the number 7 octillion has 27 zeros after it. So the number of zeros altogether is 24+27 which is 51 zeros. The difference between the number of zeros in 7 septillions and 7 thousand is 24-3 which is 21 zeros.
Question 3.
Mathematical PRACTICE 3 Justify Conclusions Three buses can carry a total of 180 students. Is there enough room on the 3 buses for 95 boys and 92 girls? Explain.
Answer:
The three buses are not enough for 95 boys and 92 girls.
Explanation:
Given that the three buses are carrying a total of 180 students and we need to check that there is enough room on the 3 buses for 95 boys and 92 girls which is 95+92 = 187. So the three buses are not enough for 95 boys and 92 girls.
Question 4.
Mrs. Carpenter received a bill for car repairs. About how much was the oil change if the other repairs were $102?
Answer:
The chargers for an oil change will be $32.
Explanation:
Given that the car repair costs $134 and the other charges are $102. So the chargers for an oil change will be $134-$102 which is $32.
Review the Strategies
Use any strategy to solve each problem.
- Determine reasonable answers.
- Determine an estimate or exact answer.
- Use the four-step plan.
Question 5.
Some children took part in a penny hunt. About how many more pennies did Pat find than either of his two friends?
Answer:
Pat finds 49 more pennies than Cynthia and 57 more pennies than Garica.
Explanation:
Given that in the penny hunt Cynthia finds 133 pennies Pat finds 182 pennies and Garica finds 125 pennies. So Pat finds 182-133 which is 49 more pennies than Cynthia and 182-125 which is 57 more pennies than Garica.
Question 6.
Mathematical PRACTICE 1 Check for Reasonableness A bank account has S320 in it on Monday. On Tuesday, $629 is added to the account. On Wednesday, $630 is taken out of the account. Is it reasonable to say that there is about $100 in the account after Wednesday? Explain.
Answer:
The answer is not reasonable.
Explanation:
Given that a bank account had $320 in it on Monday and on Tuesday, $629 is added to the account which makes $320+$629 = $949. On Wednesday, $630 is taken out of the account which is $949-$629 which is $320. So the answer was not reasonable, as the estimation is not closer to the answer.
Question 7.
When the school first opened, its library had 213 books. Today it has more than 650 books. About how many books has the school bought since it first opened? Explain.
Answer:
The number of books has the school bought since it first opened is 863 books.
Explanation:
Given that the library had 213 books when school was first opened and today it has more than 650 books. So the number of books has the school bought since it first opened is 213+650 which is 863 books.
Question 8.
The Bonilla family spent $1,679 on their vacation. The Turner family spent $983. About how much less did the Turner family spend? Explain.
Answer:
$996 less amount was spent by the Turner family.
Explanation:
Given that the Bonilla family spent $1,679 on their vacation and the Turner family spent $983. So $1,679-$983 which is $996 less amount was spent by the Turner family.
McGraw Hill My Math Grade 3 Chapter 3 Lesson 3 My Homework Answer Key
Problem Solving
Determine whether each problem requires an estimate or an exact answer. Then solve.
Question 1.
Gavin saved $53 in August and $15 in September. Is it reasonable to say he needs $50 more to pay for a karate class that costs $100? Explain.
Answer:
Yes, the answer is reasonable.
Explanation:
Given that Gavin saved $53 in August and $15 in September. Yes, it is reasonable to say he needs $50 more to pay for a karate class that costs $100. As $53+$15 is $68 and if he saves $50 more it will be $68+$50 which is $118. So the answer is reasonable.
Question 2.
There were 4,569 fans at a soccer game. The visiting team had 1,604 fans cheering. About how many fans cheered for the home team? Explain.
Answer:
The number of fans who cheered for the home team is 2,965.
Explanation:
Given that there were 4,569 fans at a soccer game and the visiting team had 1,604 fans cheering. So the number of fans who cheered for the home team is 4,569-1,604 which is 2,965.
Question 3.
Mathematical PRACTICE 1 Make Sense of Problems Luke buys 2 small pumpkins and 1 large pumpkin. How much does Luke spend?
Answer:
Luke spends $15.
Explanation:
Given that Luke bought 2 small pumpkins and 1 large pumpkin. As the cost of a small pumpkin is $4 and a large pumpkin is $7. The cost of 2 small pumpkins is 2×4 which is $8 and Luke spends $8+$7 which is $15.
Question 4.
Peyton learned that the brown bear at a local zoo weighs 1,578 pounds. About how much more does the brown bear weigh than the polar bear? Explain.
Answer:
241 pounds brown bear weighs than the polar bear.
Explanation:
Given that Peyton learned that the brown bear at a local zoo weighs 1,578 pounds and the polar bear weighs 1,337 pounds. So 1,578-1,337 which is 241 pounds brown bear weighs than the polar bear.