Go through the Math in Focus Grade 4 Workbook Answer Key Chapter 3 Whole Number Multiplication and Division to finish your assignments.
Math in Focus Grade 4 Chapter 3 Answer Key Whole Number Multiplication and Division
Math Journal
Look at each problem. Use estimation to explain why the answers are not reasonable.
Example
5,268 × 8 = 2,144
Explain.
5,268 is about 5,000
5,000 × 8 = 40,000
So the answer is too small.
Question 1.
725 × 6 = 700
Explain.
Answer:
725 is about 700
700 × 6 = 4,200
So the answer is too small.
Question 2.
497 × 21 = 1,291
Explain.
Answer:
497 is about 500
500×21 = 10,500.
So the answer is too small.
Use estimation to explain why the answer is not reasonable.
Question 3.
6,021 ÷ 3 = 207
Explain.
____
Answer:
6,021 is about 6,000
6,000 ÷ 3 = 2,000.
So the answer is too small.
Solve. Show your work.
Question 4.
Look at the number sentence.
72 ÷ 6 = 12
How would you use this to find the missing quotient?
7200 ÷ 6 = 
Answer:
7200 ÷ 6 = 1200.
Explanation:
As 72 ÷ 6 = 12, so for 7200 ÷ 6 it will be 1200.
Put on Your Thinking cap!
Challenging Practice
Charlie has 1,243 stamps. He gives away 12 stamps. His father gives him 415 stamps. He divides as many stamps as possible equally among 4 albums.
Question 1.
How many stamps did he place in each album?
Answer:
He places 411 stamps in each album.
Explanation:
Given that Charlie has 1,243 stamps and he gives away 12 stamps then it will be 1,243 – 12 = 1,231 and his father gives him 415 stamps then it will be 1,231+415 which is 1,646. As he divides as many stamps as possible equally among 4 albums it will be 1,646÷4 which will be approx 411 stamps.
Question 2.
Based on your answer in Exercise 1, how many stamps are left over?
Answer:
2 stamps.
Explanation:
The number of stamps leftover is 2 stamps.
Put on Your Thinking Cap!
Problem Solving
Question 1.
The cost of 2 televisions and 3 DVD players is $1,421. The cost of 1 DVD player is half the cost of 1 television. What is the cost of 1 television?
Answer:
Explanation:
Given that the cost of 2 televisions and 3 DVD players is $1,421 and the cost of 1 DVD player is half the cost of 1 television. Let the cost of 1 DVD player be X, so the price of the television will be 2X. So 2 televisions and 3 DVD player will be 2(2X)+3(X) = $1,421
4X+3X = $1,421
7X = $1,421
X = $203.
So the cost of 1 television it will be 2($203) which is $406.