All the solutions provided in McGraw Hill My Math Grade 5 Answer Key PDF Chapter 7 Lesson 2 Order of Operations will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 5 Answer Key Chapter 7 Lesson 2 Order of Operations
Example 1
The table shows the number of Calories burned in one minute for two different activities. Nathan swims for 4 minutes and then runs for 8 minutes. How many Calories has Nathan burned in all?
Evaluate the expression 12 × 4 + 10 × 8.
So, Nathan has burned _____________ Calories.
Answer:
12 × 4 + 10 × 8 = 128
Explanation:
Nathan swims for 4 minutes and then runs for 8 minutes.
while swimming per minute it burns 12 calories.
while running per minute it burns 10 calories.
Example 2
Evaluate 20 – {4 + [4 + (10 ÷ 2)]}
So, 20 – {4 + [4 + (10 ÷ 2)]} = _____________.
Answer:
7
Explanation:
Guided Practice
Question 1.
Evaluate {28 + (2 × 42) ÷ 8]}
So, {28 + (2 × 42) ÷ 8]} = ______________.
Answer:
{28 + (2 × 42) ÷ 8]} = 32
Explanation:
Talk Math
Explain why it is important to follow the order of operations when evaluating 15 + 3 × 4.
Answer:
Yes, it is important to follow the order of operations when evaluating to get accurate result.
15 + 3 × 4 = 15 + 12 = 27
Explanation:
The order of operations is a rule that tells the correct sequence of steps for evaluating.
We can remember the order using PEMDAS:
Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).
15 + 3 × 4 = 15 + 12 = 27
Independent Practice
Evaluate each expression.
Question 2.
5 × (92 – 18) = ___________
Answer:
370
Explanation:
5 × (92 – 18)
first subtract the given numbers 92 – 18 = 74
then multiply 5 with 74,
5 x 74 = 370
Question 3.
12 + (42) -11 = ______________
Answer:
12 + (42) -11 = 17
Explanation:
Given,
First find the square root of 4,
4 x 4 = 16
Add 12 to 16,
12 + 16 = 28
Subtract 11 from 28,
28 – 11 = 17
Question 4.
(15 – 5) × [(9 × 3) + 3] = ___________
Answer:
(15 – 5) × [(9 × 3) + 3] = 300
Explanation:
Given, (15 – 5) × [(9 × 3) + 3]
Multiply: 9 x 3 = 27
(15 – 5) × [27 + 3]
Subtract: 15 – 5 = 10
10 × [27 + 3] =
Add: 27 + 3 = 30
Multiply: 10 x 30 = 300
Question 5.
58 – 6 × 7 = ______________
Answer:
58 – 6 × 7 = 16
Explanation:
Given, 58 – 6 × 7
Multiply: 6 x 7 = 42
Subtract: 58 – 42 = 16
Question 6.
55 – [(52 × 3) – 52] = ____________
Answer:
55 – [(52 × 3) – 52] = 5
Explanation:
Given, 55 – [(52 × 3) – 52]
Find the square roots:
5 x 5 = 25
Multiply:
25 x 3 = 75
Subtract 52 = 75 – 25 = 50
55 – 50 = 5
Question 7.
7 × 10 + 3 × 30 = _____________
Answer:
7 × 10 + 3 × 30 = 160
Explanation:
Given, 7 × 10 + 3 × 30
Multiply:
7 x 10 = 70
3 x 30 = 90
Add: 70 + 90 = 160
Question 8.
22 + {[1 × (5 – 2)] × 3} = ____________
Answer:
22 + {[1 × (5 – 2)] × 3} = 13
Explanation:
Given, 22 + {[1 × (5 – 2)] × 3}
Find 22 = 4
Subtract; 5 – 2 = 3
4 + (1 x 3) x 3
Multiply: 3 x 3 = 9
Add: 4 + 9 = 13
Question 9.
{2 × [4 – (6 ÷ 2)]} × 3 = ____________
Answer:
{2 × [4 – (6 ÷ 2)]} × 3 = 6
Explanation:
Given, {2 × [4 – (6 ÷ 2)]} × 3
Divide: 6 ÷ 2 = 3
Subtract: 4 – 3 = 1
Multiply: 2 x 1 = 2
2 x 3 = 6
Algebra Find each unknown.
Question 10.
33 + 3 × 5 = k
k = ____________
Answer:
k = 42
Explanation:
Given, 33 + 3 × 5 = k
Find 33 = 3 x 3 x 3 = 27
Multiply: 3 x 5 = 15
Add: 27 + 15 = 42
Question 11.
12 – [(32 × 4) – 30] = b
b = ____________
Answer:
b = 10
Explanation:
Given, 12 – [(32 × 4) – 30] = b
Find 32 = 3 x 3 = 9
Multiply: 9 x 4 = 32
Subtract: 32 – 30 = 2
122 – 2 = 10
Problem Solving
Question 12.
Three students are on the same team for a relay race. They finish the race in 54.3 seconds. The runners’ times are shown in the table. Evaluate 54.3 – (18.8 + 17.7) to find the time of the third runner. Record your answer in the table.
Answer:
17.8 seconds.
Explanation:
Given, 54.3 – (18.8 + 17.7)
54.3 – 36.5 = 17.8
Question 13.
You can find the temperature in degrees Celsius by using the expression 5 × (°F – 32) ÷ 9. If the temperature of a cup of hot chocolate is 104°F, what is the temperature of the cup of hot chocolate in degrees Celsius?
Answer:
40°C
Explanation:
5 × (°F – 32) ÷ 9
F = 104°F
5 x (104 – 32) ÷ 9
5 x 72 ÷ 9
5 x 8 = 40°C
Question 14.
Ryan and Maggie split the cost of a $12 pizza They also have a coupon for $2 off. Evaluate (12 – 2) ÷ 2 to find the cost each person will pay.
Answer:
$5
Explanation:
Ryan and Maggie split the cost of a $12 pizza,
They also have a coupon for $2 off.
(12 – 2) ÷ 2
The cost of each person will pay,
10 ÷ 2 = 5
HOT Problems
Question 15.
Mathematical PRACTICE Plan Your Solution Write an expression using only multiplication and subtraction so that its value is 25.
Answer:
40 – (3 × 5) = 25
Explanation:
First multiply 3 x 5 = 15
then subtract the product from 40,
40 – 15 = 25.
Question 16.
Building on the Essential Question When and why does order matter?
Answer:
The order of operations are a set of rules for how to evaluate expressions.
Explanation:
The order of operations helps to calculate the problems of different combinations of operations, which must be done in the following order:
parentheses, exponents, multiplication, division, addition, and subtraction.
McGraw Hill My Math Grade 5 Chapter 7 Lesson 2 My Homework Answer Key
Practice
Question 1.
Evaluate 64 ÷ [4 × (27 – 52)].
So, 64 ÷ [4 × (27 – 52)] = ______________.
Answer:
8
Explanation:
Problem Solving
Question 2.
Mathematical PRACTICE Model Math Kishauna rode her bike for 35 minutes each on Monday, Wednesday, and Saturday and 55 minutes each on Tuesday and Thursday. Write an expression that shows the total amount of time she spent riding her bike. Then evaluate the expression.
Answer:
215 minutes.
Explanation:
There are 3 days in which Kishauna rode for 35 minutes.
35 + 35 + 35 = 105 minutes.
2 days in which she rode for 55 minutes.
55 + 55 = 110 minutes.
So, the expression:
35 + 35 + 35 + 55 + 55 or (3 x 35) + (2 x 55)
105 + 110 = 215 minutes.
Question 3.
Sarah evaluated the expression [(23 x 4) ÷ 2] + 2. What was her answer?
Answer:
18
Explanation:
Given, [(23 x 4) ÷ 2] + 2
Find 23 = 2 x 2 x 2 = 8
Multiply: 8 x 4 = 32
Divide: 32 ÷ 2 = 16
Add: 16 + 2 = 18
Question 4.
Kylie and her three friends equally divided the cost to rent a movie for $4 and order sandwiches for a total of $15. They also have a coupon for $3 off the sandwiches. Evaluate [(4 + 15) – 3] ÷ 4 to find the cost each person will pay.
Answer:
$4
Explanation:
Given, [(4 + 15) – 3] ÷ 4
Add: 4 + 15 = 19
Subtract: 19 – 3 = 16
Divided: 16 ÷ 4 = 4
Vocabulary Check
Question 5.
Fill in each blank with the correct word to complete the sentence.
The rules of the order of operations tells you to multiply and divide in order from ____________ to ____________.
Answer:
Left to Right.
Explanation:
The rules of the order of operations tells us to multiply and divide in order from left to right.
Test Practice
Question 6.
Keiko’s class collected money to donate to charity. When Keiko counted the money, there were 140 five-dollar bills, and 255 one-dollar bills. What expression could he use to find out how much money was collected?
(A) (140 × $5) + (255 × $1)
(B) (140 × $1) + (255 × $5)
(C) (140 + $5 × 255 + $1)
(D) 140 + $5 + 255 + $1
Answer:
Option(A)
Explanation:
There were 140 five-dollar bills = 140 x $5
255 one-dollar bills = 255 x $1
The expression he use to find = (140 × $5) + (255 × $1)