As we have learned in previous lessons, when working with combined operations the order of the basic operations must be followed in order to get the correct result. However, before performing these the parentheses and then the roots and powers must first be solved.
Roots are very important in mathematical calculations. They are present in a variety of exercises ranging from algebraic problems for solving a second degree equation using the general formula, to geometric problems like determining the length of the hypotenuse of a right-angled triangle. Therefore, it is fundamental that we learn how to solve combined operations where this operation appears.
When we have simplified the root and power operations, we can continue solving the exercise according to the order of the basic operations: multiplications and divisions first, followed by additions and subtractions.
Since this is not an operation that affects the rest of the operations of the exercise, we do not have to solve them from left to right as we do with the rest of the operations.
Let's look at the following example:
5+49โ+43+(10โ 3):2=
To solve it, we start by performing the operations inside the parentheses.
5+49โ+43+30:2=
Next, we move on to roots and powers.
5+7+64+30:2=
In the next step, we perform the multiplications and divisions.
5+7+64+15=
Once solved, we move on to the addition and subtraction operations.
5+7+64+15=91
Order of Operations Examples
Exercise 1
Let's consider the following example:
3+8โ1+23+(3โ 2):1=
To solve it, we start by performing the operations inside the parentheses.
3+8โ1+23+6:1=
Next, we move on to roots and powers.
3+9+23+6:1=,3+9+8+6:1=
In the next step, we perform the multiplications and divisions.
3+8+8+6=
Finally, we move on to the addition and subtraction operations.
3+8+8+6=25
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Test your knowledge
Question 1
\( 7 + \sqrt{49} - 5 = \)
Incorrect
Correct Answer:
\( 9 \)
Question 2
\( 3 \times 2 + \sqrt{81} = \)
Incorrect
Correct Answer:
\( 15 \)
Question 3
\( 8 - \sqrt{16} \times 3 = \)
Incorrect
Correct Answer:
\( -4 \)
Exercise 2
Now we will do the same exercise, but with a small variation:
3โ (8โ1+23)+3โ2:1=
Since the root and the power are inside parentheses, we first need to simplify them in order to remove the parentheses.
3โ (9+8)+3โ2:1=,3โ 17+3โ2:1=
Next, in line with the order of operations, we can move on to the multiplications and divisions (remember, from left to right). 51+3โ2:1=,51+3โ2=
Now we can proceed on to the last operations: addition and subtraction. 51+3โ2=52
Exercise 3
Now let's try this exercise:
9โ+49โ+121โร13โ(42+62)ย =
Here, we start by performing the operations inside the brackets, which in this case are powers.
9โ+49โ+121โร13โ(16+36)ย =
9โ+49โ+121โร13โ(52)ย =
9โ+49โ+121โร13โ52ย =
Next, we move on to the multiplications and divisions (remember, from left to right).
3+7+11ร13โ52=
Then the multiplications and divisions (from left to right).
3+7+143โ52=
Finally, we add and subtract. 3+7+143โ52=101
Do you know what the answer is?
Question 1
\( 10-5^2:5= \)
Incorrect
Correct Answer:
\( 5 \)
Question 2
\( 15-4^2:2= \)
Incorrect
Correct Answer:
\( 7 \)
Question 3
\( 20-3^3:3= \)
Incorrect
Correct Answer:
\( 11 \)
Exercise 4
9โโ 4โ+92โ 6=
In this exercise we see that there are no parentheses. Therefore, we solve the roots and powers first in order from left to right.
3โ 2+81โ 6=
Now we continue on to multiplications and divisions (from left to right).
6+486=
Finally, we add and subtract. 6+486=492
Exercise 5
32โ2+4โ9=
In this exercise we see that there are no parentheses either, so again we solve the roots and powers in order from left to right.
9โ2+7=
Finally, we add and subtract. 9โ2+7=14
Check your understanding
Question 1
\( 8 + 3 \times 2 - 4^2 = \)
Incorrect
Correct Answer:
\( -2 \)
Question 2
\( 6 - 3 + 5 \times 2^2 = \)
Incorrect
Correct Answer:
\( 23 \)
Question 3
\( 4 + \sqrt{49} \times 3 = \)
Incorrect
Correct Answer:
\( 25 \)
Exercise 6
327โ+(2โ)2+38โ16โโ+9โร4โ=
In order to perform the addition of roots, we start by calculating the cube root of 27, which is 3. When we square the square root of 2, the root and the power cancel each other out, leaving us with a result of 2.
3+2+38โ16โโ+9โร4โ=
In order to perform root multiplications and divisions, we first obtain the result of each root.
3+2+24โ+3ร2=
Next, we perform the division and multiplication.
3+2+2+6=
Finally, we calculate the sum.
13
Order of Operations: Root Exercises
1โ6โ 4โ+42โ 10=
122โ7+3โ6=
6+6โ4โ4=
2โ (3โ2+9)=
2โ (33+1โ44)=
(42+3)โ 9โ=
182โ(100+9โ)=
(1โ6โ22+6):22=
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Do you think you will be able to solve it?
Question 1
\( 5^2 - \sqrt{16} + 2 = \)
Incorrect
Correct Answer:
\( 23 \)
Question 2
\( 6+\sqrt{64}-4= \)
Incorrect
Correct Answer:
10
Question 3
\( 10:2-2^2= \)
Incorrect
Correct Answer:
1
Review Questions
Which is done first, division or root?
When we have combined operations where both divisions and roots appear, the root is solved first and then the division.
Which is done first, the root or the power?
Roots and the powers share the same level of importance within the order of operations. As these operations neither affect each other nor the rest of the operations, it is not necessary to perform them from right to left.
Test your knowledge
Question 1
\( 3\times3+3^2=\text{ ?} \)
Incorrect
Correct Answer:
18
Question 2
\( 8-3^2:3= \)
Incorrect
Correct Answer:
\( 5 \)
Question 3
\( 5+\sqrt{36}-1= \)
Incorrect
Correct Answer:
\( 10 \)
What is the correct order when performing mathematical operations?
When we have operations or exercises combined with different operations, we must solve them in the following order:
Operations within parentheses (The order of operations is maintained within these).
Roots and powers.
Multiplications and divisions (from left to right).
Additions and subtractions (from left to right).
How do you solve combined operations with roots?
Before solving the roots, we must solve the operations inside the parentheses. Once this has been done, we proceed with solving the roots and powers.
Do you know what the answer is?
Question 1
\( 7 + \sqrt{49} - 5 = \)
Incorrect
Correct Answer:
\( 9 \)
Question 2
\( 3 \times 2 + \sqrt{81} = \)
Incorrect
Correct Answer:
\( 15 \)
Question 3
\( 8 - \sqrt{16} \times 3 = \)
Incorrect
Correct Answer:
\( -4 \)
Examples with solutions for Order of Operations: Roots
Exercise #1
5+36โโ1=
Video Solution
Step-by-Step Solution
To solve the expression 5+36โโ1=, we need to follow the order of operations, often remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction).
Here are the steps:
First, calculate the square root:
36โ=6
Substitute the square root back into the expression:
5+6โ1
Next, perform the addition and subtraction from left to right:
Add 5 and 6:
5+6=11
Then subtract 1:
11โ1=10
Finally, you obtain the solution:
10
Answer
10
Exercise #2
10โ52:5=
Step-by-Step Solution
First, compute the power: 52=25.
Next, divide: 25รท5=5.
Finally, subtract: 10โ5=5.
Answer
5
Exercise #3
20โ33:3=
Step-by-Step Solution
First, compute the power: 33=27.
Next, divide: 27รท3=9.
Finally, subtract: 20โ9=11.
Answer
11
Exercise #4
8+3ร2โ42=
Step-by-Step Solution
First, follow the order of operations (BODMAS/BIDMAS):
Step 1: Calculate the exponent: 42=16
Step 2: Perform the multiplication: 3ร2=6
Step 3: Perform the addition and subtraction from left to right: 8+6โ16=14โ16=โ2
The correct result is: โ2.
Answer
โ2
Exercise #5
3ร2+81โ=
Step-by-Step Solution
First, evaluate the square root: 81โ=9.
Then, follow the order of operations (PEMDAS/BODMAS):