All the solutions provided in McGraw Hill Math Grade 3 Answer Key PDF Chapter 4 Lesson 2 Multiplication as Repeated Addition will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 3 Answer Key Chapter 4 Lesson 2 Multiplication as Repeated Addition
Math in My World
Example 1
Gilberto made 4 small pizzas for his party. Each pizza had 5 slices of tomato. How many slices of tomato did Gilberto use to make 4 small pizzas?
Find how many slices of tomato there are in 4 groups of 5.
One Way Draw a picture.
1. There are ____ groups. Draw 4 pizzas.
2. There are ____ in each group. Draw 5 slices of tomato on each pizza.
3. Count. There are slices of tomato.
Another Way Use repeated addition. Write an addition sentence to show the equal groups.
____ + ____ + ____ + ____ = ____
So, ___ groups of ____ is ____.
Gilberto used ____ slices of tomato
Answer:
Explanation:
Gilberto made 4 small pizzas for his party
Each pizza had 5 slices of tomato
There are 4 groups
I drew 4 pizzas
There are 5 in each group.
I drew 5 slices of tomato on each pizza
I counted by 1’s there are 20 slices of tomato.
Another Way Use repeated addition
The addition sentence to show the equal groups
5 + 5 + 5 + 5 = 20
So, 4 groups of 5 is 20
Gilberto used 20 slices of tomato.
When you find the total of equal groups of objects, you multiply. The symbol (×) means to multiply. The numbers multiplied are factors. The result is the product.
Example 2
A honeycomb cell has 6 sides. How many sides do 5 separated honeycomb cells have?
Find 5 groups of 6.
One Way Write an addition sentence.
Use five 6-sided pattern blocks. Count the number of sides in all.
Another Way Write a multiplication sentence.
So, ____ groups of 6 is ____. The unknown is ___ sides.
Answer:
Explanation:
I drew five 6-sided pattern blocks
I wrote an addition sentence
6 + 6 + 6 + 6 + 6 = 30
So, 5 groups of 6 is 30
The total number of sides is 30.
Another way:
Use multiplication sentence
Number of groups are 5
Number of sides are 6
5 x 6 = 30
So, 5 groups of 6 is 30. The unknown is 30 sides.
Talk Math
Can you write 2 + 3 + 4 = 9 as a multiplication sentence? Explain.
Answer:
No, we cannot write the addition sentence 2 + 3 + 4 = 9 as a multiplication sentence because it does not have equal numbers.
Guided Practice
Question 1.
Write an addition sentence and a multiplication sentence.
____ + ____ + ____ + ____ = ____
____ × ____ = ____
Answer:
3 + 3 + 3 + 3 = 12
4 x 3 = 12
Explanation:
There are 4 groups of 3 ants
4 groups of 3
Use repeated addition
An addition sentence to show the equal groups
3 + 3 + 3 + 3 = 12
Use multiplication
The multiplication sentence is
4 x 3 = 12.
Independent Practice
Write an addition sentence and a multiplication sentence for each.
Question 2.
____ + ___ + ____ = _____
____ × ____ = ____
Answer:
2 + 2 + 2 = 6
3 x 2 = 6
Explanation:
There are 3 groups of 2 butterflies
3 groups of 2
Use repeated addition
An addition sentence to show the equal groups
2 + 2 + 2 = 6
Use multiplication
The multiplication sentence is 3 x 2 = 6.
Question 3.
___ + ____ = _____
____ × ____ = ____
Answer:
4 + 4 = 8
2 x 4 = 8
Explanation:
There are 2 groups of 4 planes
2 groups of 4
Use repeated addition
An addition sentence to show the equal groups
4 + 4 = 8
Use multiplication
The multiplication sentence is 2 x 4 = 8.
Question 4.
___ + ____ + ____ + ____ + ___ + ____ = _____
____ × ____ = ____
Answer:
3 + 3 + 3 + 3 + 3 + 3 = 18
6 x 3 = 18
Explanation:
There are 6 groups of 3 balls
6 groups of 3
Use repeated addition
An addition sentence to show the equal groups
3 + 3 + 3 + 3 + 3 + 3 = 18
Use multiplication
The multiplication sentence is 6 x 3 = 18.
Question 5.
___ + ____ + ___ + ____ + ____ + ____ + ___ + ____ = _____
____ × ____ = ____
Answer:
2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 16
8 x 2 = 16
Explanation:
There are 8 groups of 2 cockroaches
8 groups of 2
Use repeated addition
An addition sentence to show the equal groups
2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 16
Use multiplication
The multiplication sentence is 8 x 2 = 16.
Draw a picture to find the total. Write a multiplication sentence.
Question 6.
6 groups of 5
____ × ____ = ____
Answer:
Explanation:
I drew 6 groups of 5 counters in each group
6 groups of 5
The multiplication sentence is
6 x 5 =
Use repeated addition
5 + 5 + 5 + 5 + 5 + 5 = 30
So, 6 x 5 = 30
Therefore, 6 groups of 5 is 30.
Question 7.
8 groups of 4
____ × ____ = ____
Answer:
Explanation:
I drew 8 groups of 4 counters in each group
8 groups of 4
The multiplication sentence is
8 x 4 = 32
Use repeated addition
4 + 4 + 4 + 4 + 4 + 4 + 4 + 4 = 32
So, 8 x 4 = 32
Therefore, 8 groups of 4 is 32.
Algebra Multiply to find the unknown product.
Question 8.
3 × 5 = 
The unknown is ____.
Answer:
15
Explanation:
3 x 5 =
Use repeated addition
5 + 5 + 5 = 15
So, 3 x 5 = 15
Therefore, the unknown number is 15.
Question 9.
5 × 2 =
The unknown is ____.
Answer:
10
Explanation:
5 x 2 =
Use repeated addition
2 + 2 + 2 + 2+ 2 = 10
So, 5 x 2 = 10
Therefore, the unknown number is 10.
Question 10.
3 × 3 =
The unknown is ____.
Answer:
9
Explanation:
3 x 3 =
Use repeated addition
3 + 3 + 3 = 9
So, 3 x 3 = 9
Therefore, the unknown number is 9.
Problem Solving
Algebra Write a multiplication sentence with a symbol for the unknown. Then solve.
Question 11.
Adriano bought 3 boxes of paints. Each box has 8 colors. What is the total number of colors?
3 × 8 =
3 × 8 = ____ colors
Answer:
24
Explanation:
3 x 8 =
Use repeated addition
8 + 8 + 8 = 24
So, 3 x 8 = 24
Therefore, the number of colors is 24.
Question 12.
Three boys each have 5 balloons. How many balloons do they have altogether?
____ × ___ = ____
____ × ____ = _____ balloons
Answer:
3 x 5 = 15
Explanation:
3 x 5 =
Use repeated addition
5 + 5 + 5 = 15
So, 3 x 5 = 15
Therefore, they have altogether 15 balloons.
HOT problems
Question 13.
Mathematical PRACTICE 4 Model Math Write a real-world problem for the model. Write a multiplication sentence to find the total.
Answer:
There are 5 trays of eggs. Each tray consists of 6 eggs. How many eggs are there in all the 5 trays.
Explanation:
5 groups of 6
5 x 6 =
Use repeated addition
6 + 6 + 6 + 6 + 6 = 30
So, 5 x 6 = 30 is the multiplication sentence that tells the total.
Question 14.
Mathematical PRACTICE 2 Use Number Sense What is 2 more than 5 groups of 3? _____
Answer:
2 more than 5 groups of 3 is 17
Explanation:
5 groups of 3
5 x 3 =
Use repeated addition
3 + 3 + 3 + 3 + 3 = 15
So, 5 groups of 3 is 15
Add 2 to 15
15 + 2 = 17
So, 2 more than 5 groups of 3 is 17.
Question 15.
? Building on the Essential Question How are multiplication and repeated addition alike?
Answer:
Multiplication is nothing but the repeated process of addition. We can express the multiplication as the repeated addition of the same number. It is one of the arithmetic operations. The symbol of multiplication is “x”. Multiplying a 1-Digit Number means multiplying one-digit number by another one-digit number.
McGraw Hill My Math Grade 3 Chapter 4 Lesson 2 My Homework Answer Key
Practice
Write an addition sentence and a multiplication sentence for each.
Question 1.
6 + 6 + ___ + ___ + ___ = ____
____ × ____ = ____
Answer:
6 + 6 + 6 + 6 + 6 = 30
5 x 6 = 30
Explanation:
5 groups of 6
Use Repeated addition
6 + 6 + 6 + 6 + 6 = 30
Use multiplication
5 x 6 = 30
So, 6 + 6 + 6 + 6 + 6 = 30
5 x 6 = 30.
Explanation:
Question 2.
____ + ___ + ___ + ___ = ____
____ × ____ = ____
Answer:
5 + 5 + 5 + 5 = 20
4 x 5 = 20
Explanation:
4 groups of 5
Use Repeated addition
5 + 5 + 5 + 5 = 20
Use multiplication
4 x 5 = 20
So, 5 + 5 + 5 + 5 = 20
4 x 5 = 20.
Problem Solving
Draw a picture to find the total. Write a multiplication sentence.
Question 3.
7 groups of 1 green grape
____ × ____ = ____
Answer:
Explanation:
7 groups of 1 green grape
7 x 1 = 7
So, the total is 7.
Question 4.
9 groups of 2 square crackers
____ × ____ = ____
Answer:
Explanation:
9 groups of 2 square crackers
9 x 2 =
Use repeated addition
2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 18
9 x 2 = 18
So, the total is 18.
Question 5.
Mathematical PRACTICE 4 Model Math How many buttons does Leonora have altogether if she has 4 bags of buttons and each bag has 10 buttons?
____ × ____ = ____
Answer:
Explanation:
Leonora has 4 bags of buttons
Each bag has 10 buttons
4 x 10 =
Use repeated addition
10 + 10 + 10 + 10 = 40
So, 4 x 10 = 40
Therefore, Leonora has 40 buttons altogether.
Multiply to find the unknown product.
Question 6.
8 × 3 = 
The unknown is ___.
Answer:
24
Explanation:
3 x 8 =
Use repeated addition
8 + 8 + 8 = 24
So, 3 x 8 = 24
Therefore, the unknown number is 24.
Question 7.
4 × 3 =
The unknown is ___.
Answer:
12
Explanation:
4 x 3 =
Use repeated addition
4 + 4 + 4 = 12
So, 4 x 3 = 12
Therefore, the unknown number is 12.
Vocabulary Check
Use the correct word(s) and the number sentence 6 × 8 = 48 to solve.
equal groups repeated addition multiply factors product
Question 8.
The number 48 is the ______
Answer:
The number 48 is the product.
Question 9.
The symbol × tells you to ____
Answer:
The symbol × tells you to multiply.
Question 10.
The numbers 6 and 8 are the ____
Answer:
The numbers 6 and 8 are the factors.
Question 11.
8 + 8 + 8 + 8 + 8 + 8 = 48 shows _____
Answer:
8 + 8 + 8 + 8 + 8 + 8 = 48 shows repeated addition.
Question 12.
6 × 8 means 6 _____ of 8.
Answer:
6 × 8 means 6 equal groups of 8.
Test Practice
Question 13.
Sam is washing windows. There are 5 windows in each of 7 rooms. How many windows does Sam have to wash?
A. 2 windows
B. 12 windows
C. 30 windows
D. 35 windows
Answer:
D. 35 windows
Explanation:
Sam is washing windows
There are 5 windows in each of 7 rooms
7 groups of 5
Use repeated addition
An addition sentence to show the equal groups
5 + 5 + 5 + 5 + 5 + 5 + 5 = 35
Use multiplication
The multiplication sentence is 7 x 5 = 35
So, Sam have to wash 35 windows.