More arithmetic rules: subtraction of a sum, subtraction of a difference, division by product, and division by quotient

In this article, we will dive into the world of essential arithmetic rules that are fundamental for tackling a wide variety of mathematical exercises. Mastering these rules will provide you with a solid foundation and allow you to solve problems with greater confidence and precision. From basic operations like addition and subtraction to more advanced concepts like the division of products and quotients, we will explore each of these rules in detail. Are you ready to deepen your mathematical skills?
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Test yourself on additional arithmetic rules!

\( 100-(5+55)= \)

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Subtraction of a sum

Sometimes we need to subtract a sum of elements from another element.
Rule:
aโˆ’(b+c)=aโˆ’bโˆ’caโˆ’(b+c)=aโˆ’bโˆ’c

  • This is also true in algebraic expressions.

We can operate according to the rule: apply the subtraction sign to each of the elements included in the parentheses.
Likewise, we can act according to the order of mathematical operations starting with the parentheses - calculate the sum and only then subtract it.

For example, in the exercise:
21โˆ’(7+2)=21-(7+2)=

Option 1 - according to the rule:

We will subtract each element in the parentheses separately and it will give us:
21โˆ’7โˆ’2=1221-7-2=12

Option 2 - according to the order of operations:

Subtraction of a difference

It is valid when we need to subtract a difference of elements from another element.
Rule:
aโˆ’(bโˆ’c)=aโˆ’b+caโˆ’(b-c)=a-b+c

We can operate according to the rule: apply the subtraction sign to each of the elements included in the parentheses and always remember that, minus times minus gives plus.
Likewise, we can act according to the order of mathematical operations starting with the parentheses - calculate the difference and only then subtract it.

For example, in the exercise:
33โˆ’(9โˆ’3)=33-(9-3)=

Option 1 - according to the rule:

We will separately subtract each element in the parentheses and it will give us:
33โˆ’9+3=33-9+3=

24+3=2724+3=27

Option 2 - according to the order of operations:

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Division by product

It is also true when we need to divide a certain element by the product of others.
Rule:
a:(bโ‹…c)=a:b:ca:(b\cdot c)=a:b:c

  • This is also valid in algebraic expressions.

We can operate according to the rule: apply the division to each of the elements included in the parentheses.
Likewise, we can act according to the order of mathematical operations starting with the parentheses - calculate the multiplication and only then divide by the product.

For example, in the exercise:
50:(2โ‹…5)50:(2\cdot5)

Option 1 - according to the rule:

We will divide separately for each element of the parentheses and it will give us:
50:2:5=50:2:5=
First, we will divide 50:250:2 and rewrite the exercise:
25:5=525:5=5

Option 2 - according to the order of operations:

Division by quotient

It is valid when we need to divide a certain element by the quotient of others.
Rule:
a:(b:c)=a:bโ‹…cย a:(b:c)=a:b\cdot cย 

  • This is also valid in algebraic expressions.

We can operate according to the rule: apply the division to the first element inside the parentheses and then apply the multiplication to the second element of the parentheses.
Likewise, we can act according to the order of mathematical operations starting with the parentheses - calculate the quotient and only then divide by it.

For example, in the exercise:
48:(6:2)=48:(6:2)=

Option 1 - according to the rule:

We will apply division to the first element inside the parentheses and then multiply by the second element of the parentheses.

48:6โ‹…2=48:6\cdot2=
First, we will divide 48:648:6 and rewrite the exercise:
8โ‹…2=168\cdot 2=16

Option 2 - according to the order of operations:

48:(6:2)=48:(6:2)=
48:3=1648:3=16

Click here for a more detailed explanation about division by quotient.


Examples and exercises with solutions of arithmetic rules

Exercise #1

15:(2ร—5)= 15:(2\times5)= ?

Video Solution

Step-by-Step Solution

First we need to apply the following formula:

a:(bร—c)=a:b:c a:(b\times c)=a:b:c

Therefore, we get:

15:2:5= 15:2:5=

Now, let's rewrite the exercise as a fraction:

1525= \frac{\frac{15}{2}}{5}=

Then we'll convert it to a multiplication of two fractions:

152ร—15= \frac{15}{2}\times\frac{1}{5}=

Finally, we multiply numerator by numerator and denominator by denominator, leaving us with:

1510=1510=112 \frac{15}{10}=1\frac{5}{10}=1\frac{1}{2}

Answer

112 1\frac{1}{2}

Exercise #2

10:(10:5)= 10:(10:5)=

Video Solution

Step-by-Step Solution

To solve the expression 10:(10:5) 10 : (10 : 5) , we will apply the order of operations systematically.

Step 1: Evaluate the inner division 10:5 10 : 5 .
When we compute 10:5 10 : 5 , we are finding how many times 5 fits into 10. This calculation can be expressed as:
105=2 \frac{10}{5} = 2 .

Step 2: Substitute the result from step 1 into the outer division.
Now, we substitute 10:(10:5) 10 : (10 : 5) with 10:2 10 : 2 . Once again, we apply division:
102=5 \frac{10}{2} = 5 .

Therefore, the solution to the expression 10:(10:5) 10 : (10 : 5) is 5 5 .

Answer

5 5

Exercise #3

18:(6ร—3)= 18:(6\times3)=

Video Solution

Step-by-Step Solution

To solve the expression 18รท(6ร—3) 18 \div (6 \times 3) , we need to follow the order of operations, which specifies that multiplication should be performed before division. Therefore, we proceed as follows:

  • Step 1: Calculate the operation inside the parentheses: (6ร—3)(6 \times 3).
    We multiply 66 by 33 to get 1818.
  • Step 2: Replace the multiplication expression in the original division: 18รท1818 \div 18.
  • Step 3: Perform the division: 18รท18=118 \div 18 = 1.

Thus, the result of the expression 18รท(6ร—3) 18 \div (6 \times 3) is 1\mathbf{1}.

Answer

1

Exercise #4

2โˆ’(1+1)= 2-(1+1)=

Video Solution

Step-by-Step Solution

To solve the expression 2โˆ’(1+1) 2 - (1 + 1) , follow these steps:

  • First, evaluate the expression inside the parentheses: 1+1 1 + 1 .
  • This gives 2 2 .
  • Now replace the parentheses with this result, transforming the expression to 2โˆ’2 2 - 2 .
  • The result of 2โˆ’2 2 - 2 is 0 0 .

Therefore, the solution to the expression is 0 0 .

Answer

0

Exercise #5

19โˆ’(5+11)= 19-(5+11)=

Video Solution

Step-by-Step Solution

To solve the problem 19โˆ’(5+11)19 - (5 + 11), we will follow these steps:

  • Step 1: Evaluate the expression inside the parentheses. This means we need to calculate 5+115 + 11.
  • Step 2: Once the sum inside the parentheses is found, subtract this sum from 19.

Let's work through each step:

Step 1: Calculate 5+115 + 11 which equals 16.

Step 2: Substitute 16 in place of 5+115 + 11 in the original expression. You have 19โˆ’1619 - 16.

Now, solve 19โˆ’1619 - 16, which equals 3.

Therefore, the solution to the problem is 33.

Answer

3

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