All the solutions provided in McGraw Hill Math Grade 3 Answer Key PDF Chapter 5 Lesson 3 Relate Division and Subtraction will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 3 Answer Key Chapter 5 Lesson 3 Relate Division and Subtraction
Math in My World
Example 1
A designer makes 15 dresses in equal numbers of red, blue, or yellow. How many dresses of each color are there? Write a division sentence with a symbol for the unknown. Then solve.
15 ÷ 3 = 
← unknown
Answer:
One Way Use models.
Draw one counter at a time on each dress until all 15 counters are gone.
There are ____ dresses of each color. The unknown is ____.
So, ___ ÷ ____ = ____
Answer:
15 dresses of each color. The unknown is 5
15 ÷ 3 = 5
Explanation:
Let the unknown be x
15 ÷ 3 = x
5 = x
There are 15 dresses of each color. The unknown is 5.
Another Way Use a number line.
You can also divide using repeated subtraction. Subtract equal groups of 3 repeatedly until you get to zero.
You subtracted groups of three ____ times.
So, 15 ÷ 3 = ____
Answer:
5 times
Explanation:
Subtract equal groups of 3 repeatedly until you get to zero. Therefore we subtracted groups of three 5 times.
Example 2
Use repeated subtraction to find 10 ÷ 2. Write a division sentence.
One Way Use a number line.
Start at 10. Count back by 2s until you reach 0. How many times did you subtract?
So, 10 ÷ 2 = ____
Answer:
5 times
Explanation:
By counting back 2s until we reach 0 is 5 times
10 ÷ 2 = 5 times
Another Way Use repeated subtraction.
Subtract groups of 2 until you reach 0. How many groups did you subtract? _____
Answer:
5 groups.
Explanation:
Here we need to subtract groups of 2 until you reach 0.
Now by counting the number of subtractions we have 5 groups.
Guided Practice
Algebra Write a division sentence with a symbol for the unknown. Then solve.
Question 1.
There are 16 flowers. Each vase has 4 flowers. How many vases are there?
____ ÷ 4 = 
There are ____ vases.
Answer:
16 ÷ 4 = 4 vases.
Explanation:
Given,
No of the flowers are 16
No of the flowers in each vase is 4
16 ÷ 4 = 4 vases.
Therefore there are a total of 4 vases.
Question 2.
There are 14 ears. Each dog has 2 ears. How many dogs are there?
____ ÷ 4 =
There are ____ dogs.
Answer:
14 ÷ 2 = 7 dogs.
Explanation:
Given,
No of ears = 14
No of ears each dog has = 2
The difference gives us the no of dogs are there
14 ÷ 2 = 7 dogs.
Talk Math
Explain how to use a number line to find 18 ÷ 9.
Answer:
18 ÷ 9 = 2
Explanation:
Use repeated subtraction to divide.
Question 3.
Answer:
4
Explanation:
First subtract equal groups of 3 repeatedly until you get to zero.
For 12 ÷ 3 = 4 start from 12.
You subtracted groups of three 4 times.
Question 4.
Answer:
4
Explanation:
First, subtract equal groups of 2 repeatedly until you get to zero.
For 8 ÷ 2 = 4 start from 8.
You subtracted groups of three 4 times.
Independent Practice
Algebra Write a division sentence with a symbol for the unknown. Then solve.
Question 5.
There are 16 orange slices. Each orange has 8 slices. How many oranges are there?
Answer:
16 ÷ 8 = 2 oranges.
Explanation:
Given,
No of orange slices = 16
Each orange has 8 slices.
Hence there are a total of 2 oranges.
Question 6.
There are 16 miles. Each trip is 2 miles. How many trips are there?
Answer:
16 ÷ 2 = 8 miles
Explanation:
Given,
No of miles = 16
Each trip has 2 miles.
To find: How many trips are there?
16 ÷ 2 = 8 trips.
There are a total of 8 trips.
Question 7.
There are 25 marbles, with 5 marbles in each bag. How many bags are there?
Answer:
25 ÷ 5 = 5 bags
Explanation:
Given,
No of marbles = 25
Each bag has 5 marbles.
We have to find out how many bags are there.
25 ÷ 5 = 5 bags.
Question 8.
Four friends will share 12 muffins equally. How many muffins will each friend get?
Answer:
12 ÷ 4 = 3 muffins
Explanation:
Given,
There are 4 friends
These friends will share 12 muffins equally.
12 ÷ 4 = 3 muffins
Therefore each friend will get 3 muffins.
Use repeated subtraction to divide.
Question 9.
10 ÷ 5 = ____
Answer:
2
Explanation:
First, subtract equal groups of 5 repeatedly until you get to zero.
For 10 ÷ 5 = 2 start from 10.
You subtracted groups of three 2 times.
Question 10.
6 ÷ 3 = ____
Answer:
2
Explanation:
First, subtract equal groups of 3 repeatedly until you get to zero.
For 6 ÷ 3 = 2 start from 6.
You subtracted groups of three 2 times.
Question 11.
9 ÷ 3 = ____
Answer:
3
Explanation:
First, subtract equal groups of 3 repeatedly until you get to zero.
For 9 ÷ 3 = 3 start from 9.
You subtracted groups of three 3 times.
Question 12.
8 ÷ 4 = ____
Answer:
2
Explanation:
First subtract equal groups of 2 repeatedly until you get to zero.
For 8 ÷ 4 = 2 start from 8.
You subtracted groups of three 2 times.
Question 13.
12 ÷ 3 = _____
Answer:
4
Explanation:
Question 14.
20 ÷ 4 = _____
Answer:
5
Explanation:
Problem Solving
Chicago’s Ferris wheel is 10 stories tall. Each cart can seat up to 6 people for a 7-minute ride.
Write a division sentence with a symbol for the unknown. Then solve.
Question 15.
It costs $24 for 4 people to ride the Ferris wheel. How much does each ticket cost?
Answer:
$24 ÷ 4 = $6
Explanation:
Given,
Cost $24 to ride the Ferris wheel.
There are 4 people riding the Ferris wheel.
Hence each ticket cost $24 ÷ 4 = $6
Question 16.
Mathematical PRACTICE 2 Use Symbols If 30 students from a class wanted to ride, how many carts would they need?
Answer:
30 ÷ 6 = 5 carts
Explanation:
Given,
No of the students from the class wanted to ride = 30
Each cart can seat up to 6 people.
30 ÷ 6 = 5 carts
HOT Problems
Question 17.
Mathematical PRACTICE Reason How can knowing that multiplication is repeated addition and division is repeated subtraction help you to understand that multiplication and division are related?
Answer:
We all know that subtraction is the opposite of addition, the division is related to subtraction, and multiplication to addition therefore we can assume that division is the opposite of multiplication.
Question 18.
? Building on the Essential Question How is division related to subtraction?
Answer:
Repeated Subtraction is a method that helps to subtract an equal number of items from a group, also known as division. By using this method, the same number is subtracted repeatedly from another bigger number until the remainder is zero.
McGraw Hill My Math Grade 3 Chapter 5 Lesson 3 My Homework Answer Key
Practice
Use repeated subtraction to divide.
Question 1.
14 ÷ 2 = ____
Answer:
7
Explanation:
First, subtract equal groups of 2 repeatedly until you get to zero.
For 14 ÷ 2 = 7 start from 14.
You subtracted groups of three 7 times.
Question 2.
12 ÷ 6 = ____
Answer:
2
Explanation:
First, subtract equal groups of 2 repeatedly until you get to zero.
For 12 ÷ 6 = 2 start from 12.
You subtracted groups of three 2 times.
Question 3.
28 ÷ 7 = ____
Answer:
4
Explanation:
Question 4.
30 ÷ 10 = ____
Answer:
3
Explanation:
Problem Solving
Algebra Write a division sentence with a symbol for the unknown. Then solve.
Question 5.
There are 24 juice bottles, with 6 bottles in each package. How many packages of juice bottles are there?
Answer:
There are a total of 4 packages of juice bottles.
Explanation:
Given,
There are 24 juice bottles.
Each package has 6 bottles.
find 24 ÷ 6
Cross out the common factor.
The answer to the given problem is 4.
There are a total of 4 packages of juice bottles.
Question 6.
A mechanic equally divides 4 hours of his time to repair 8 cars. How many cars does he repair in one hour?
Answer:
He repairs 2 cars in one hour.
Explanation:
Given,
A mechanic equally divides 4 hours of his time
And repairs 8 cars
Divide 8 cars by 4 hours which gives us 2 cars every hour.
Question 7.
On Monday, Helen’s math teacher gave the class 45 problems to finish by Friday. Helen will do the same number of problems each day. How many problems will she do on Friday?
Answer:
Helen does 9 problems on Friday.
Explanation:
Given,
45 problems to finish by Friday
How many problems will she complete in 5 days?
45 ÷ 5
9
Hence Helen does 9 problems on Friday.
Vocabulary Check
Choose the correct word(s) to complete each sentence.
number line repeated subtraction
Question 8.
Skip count backward on a _____ to divide.
Answer:
Number line.
Explanation:
Skip count backward on a number line to divide.
Question 9.
Use _____ to subtract equal groups repeatedly until you reach zero.
Answer:
Repeated subtraction.
Explanation:
Use repeated subtraction to subtract equal groups repeatedly until you reach zero.
Test Practice
Question 10.
Sal made 6 cups of oatmeal for himself and his 2 brothers. Each received an equal number of cups of oatmeal. Which number sentence represents this problem?
A. 6 – 2 = 4
B. 6 ÷ 3 = 2
C. 6 × 2 = 12
D. 6 – 3 = 3
Answer:
6 ÷ 3 = 2
Explanation:
Based on the given question
Calculate 6 ÷ (2 + 1)
6 ÷ 3 = 2
Hence the number sentence representing this problem is 6 ÷ 3 = 2.