All the solutions provided in McGraw Hill Math Grade 4 Answer Key PDF Chapter 3 Lesson 4 Compare to Solve Problems will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 4 Answer Key Chapter 3 Lesson 4 Compare to Solve Problems
Math in My World
Example 1
Bryan has been to a water park 4 times. Sarah has been to the water park three times as many times as Bryan. How many times has Sarah been to the water park?
Write an equation to find the unknown. You can use a letter, or a variable, to represent the unknown.
4 × ___ = s ← the unknown: the number of times Sarah has been to the water park
Draw a picture to show 3 times as many as 4, or 3 groups of 4.
The picture shows a total of 12.
So, 4 × 3 = 12.
Since s = ____, Sarah has been to the water park ___ times.
Answer:
Given that,
Bryan has been to a water park 4 times.
Sarah has been to the water park 3 times as many times as Bryan.
So, 4 x 3 = 12.
The unknown is 12.
The picture of 3 groups of 4 is
Since s = 12,
Sarah has been to the water park 12 times.
Example 2
Jess has 18 baseball cards. She has 6 times as many baseball cards as Max. How many baseball cards does Max have?
Write an equation. Let 
represent the number of baseball cards that Max has.
× ___ = ____
Since × 6 = 18, you know that 18 ÷ 6 = ← Use a fact family
Draw 6 equal groups of squares. Draw a total of 18 squares.
There are ___ squares in each group.
= 3. So, Max has ____ baseball cards
Answer:
Given that,
Jess has 18 baseball cards.
She has 6 times as many baseball cards as Max.
18 ÷ 6 = 3.
Draw 6 equal groups of squares.
There are 3 squares in each group.
So, Max has 3 baseball cards.
Talk Math
How can unknown numbers be represented equations?
Answer:
The variable letter or a symbol is used to represent the unknown.
Guided Practice
Question 1.
Sue has 3 times as many beads as Jo. Jo has 8 beads. How many beads does Sue have? Write an equation to find the unknown number. Use a variable for the unknown.
3 × ___ = b
b = ____
Answer:
Given that,
Sue has 3 times as many beads as Jo.
Jo has 8 beads.
The equation to find the unknown is
3 x 8 = 24.
b = 24.
The unknown is 24.
Therefore the Sue has 24 beads.
Independent Practice
Algebra Write an equation to find the unknown number. Use a symbol for the unknown.
Question 2.
Paul drew 4 times as many pictures as Dennis. Paul drew 16 pictures. How many pictures did Dennis draw?
Answer:
Given that,
Paul drew 4 times as many pictures as Dennis.
Paul drew 16 pictures.
The number of pictures that Dennis draw is 16/4 = 4.
Therefore Dennis draw 4 pictures.
Question 3.
Maria made 21 cupcakes. This is three times as many as the number of cupcakes that Mary made. How many cupcakes did Mary make?
Answer:
Given that,
Maria made 21 cupcakes.
This is three times as many as the number of cupcakes that Mary made.
So, 21 ÷ 3 = 7.
3 times of 7 is 21.
Therefore the number of cupcakes that Mary made is 7.
Algebra Write an equation to find the unknown number. Use a variable for the unknown.
Question 4.
Wendy has dance class 2 days a week. James has dance class 5 times a week. How many more times a week does James have dance class than Wendy?
Answer:
Given that,
Wendy has dance class 2 days a week.
James has dance class 5 times a week.
The number of times that James have dance class than Wendy is 5 – 2 = 3.
Therefore James have 3 dance class than Wendy.
Question 5.
There are 4 fewer white bunnies than gray bunnies. There are 9 white bunnies. How many gray bunnies are there?
Answer:
Given that,
There are 9 white bunnies.
The white bunnies are 4 fewer than gray bunnies.
The gray bunnies are 9 + 4 = 13.
Therefore there are 13 gray bunnies.
Use the table for Exercises 6-9.
Question 6.
How many more shoes were sold than belts?
________
Answer:
Given that,
The number of belts sold is 2.
The number of shoes are 7.
Shoes more then belts are 7 – 2 = 5.
Therefore there are 5 shoes sold than belts.
Question 7.
Which item sold 2 times as many as shirts?
Answer:
Given that,
The number of hats sold are 4.
The number of shits sold are 8
So, 8 ÷ 4 = 2.
Therefore hats sold 2 times as many as shirts
Question 8.
Which exercises on this page used addition or subtraction to compare? List them.
Answer:
The exercise 6 used the subtraction to compare.
Question 9.
Which exercises on this page used multiplication or division to compare? List them.
Answer:
The exercise 7 used the division to compare.
Problem Solving
Question 10.
Jerry read 24 pages this weekend. That is 4 times as many pages as what he read last weekend. How many pages did he read last weekend?
Answer:
Given that,
Jerry read 24 pages this weekend.
That is 4 times as many pages as what he read last weekend.
The number of pages that he read on last week is 24 x 4 = 96.
Therefore Jerry read 96 pages on last week.
Question 11.
A bean plant is 3 inches tall. A corn plant is five times as tall. How many inches tall is the corn plant?
Answer:
Given that,
A bean plant is 3 inches tall.
A corn plant is five times as tall.
The corn plant has 3 x 5 = 15.
Therefore the corn plant has 15 inches tall.
Question 12.
Mathematical PRACTICE 1 Plan Your Solution Hannah used 10 more blocks than Steve. Steve used 7 blocks. How many blocks did Hannah use?
Answer:
Given that,
Hannah used 10 more blocks than Steve.
Steve used 7 blocks.
The blocks that Hannah has 10 + 7 = 17.
Therefore Hannah use 17 blocks.
Question 13.
There are 10 fewer robins than cardinals. There are 16 cardinals. How many robins are there?
Answer:
Given that,
There are 10 fewer robins than cardinals.
There are 16 cardinals.
So, 16 – 10 = 6.
Therefore there are 6 robins are there.
HOT Problems
Question 14.
Mathematical PRACTICE 1 Check for Reasonableness Missy earned three times as many points as Jerry. Kimmie earned 9 more points than Jerry. Missy earned 21 points. How many points did Kimmie earn?
Answer:
Given that,
Missy earned three times as many points as Jerry.
Kimmie earned 9 more points than Jerry.
Missy earned 21 points.
So, k = j + 9.
j = 7.
k = 7 + 9.
k = 16.
Therefore Kimmie earn 16 points.
Question 15.
? Building on the Essential Question How can you tell the difference between additive comparison and multiplicative comparison?
Answer:
In additive comparison we find the relation between two amounts which is more or less. In multiplication comparison the two different sets are being compared. the first set has the number of items and the second set has the multiple of first set.