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mathsFractionsNumerical Expressions with Fractions

### Fraction: Simplification of Expressions

In this page, handling of fractions, both positive and negative fractions, in numerical expressions is explained.

The precedence order PEMDAS / BODMAS is explained.

For operations of same precedence order, the sequence of operation "simplification from left to right" is explained.

click on the content to continue..

Let us quickly revise what is numerical expression, and precedence order, sequence in simplifying the numerical expressions. This was introduced in whole numbers and reviewed in integers too. It takes very little time to revise.

What is 2+4+3?

• 9
• 9
• 243

The answer is "9".

This is an example of a numerical expression.

Which of the following is a meaning for the word "expression"?

• something done very fast
• collection of numbers and arithmetic operations between them, which together represent a quantity
• collection of numbers and arithmetic operations between them, which together represent a quantity

The answer is "collection of numbers and arithmetic operations between them, which together represent a quantity".

What is 2xx4xx3?

• 24
• 24
• 243

The answer is "24".

This is an example of a numerical expression.

Is a+3x a numerical expression?

• Yes. It has the number 3.
• No. It is not entirely numbers and arithmetic operations
• No. It is not entirely numbers and arithmetic operations

The answer is "No. It is not entirely numbers and arithmetic operations".

Solved Exercise Problem:

Is 3+4-2+1 a numerical expression?

• No, it has both addition and subtraction
• Yes, addition and subtraction can be part of a numerical expression
• Yes, addition and subtraction can be part of a numerical expression

The answer is "Yes, addition and subtraction can be part of an expression".

Solved Exercise Problem:

Is 3+4xx2-6-:3 a numerical expression?

• No, as it has the addition, subtraction, multiplication, division
• Yes, all arithmetic operations can be part of a numerical expression
• Yes, all arithmetic operations can be part of a numerical expression

The answer is "Yes, all arithmetic operations can be part of a numerical expression"

Solved Exercise Problem:

is 3 a numerical expression?

• No. 3 is only a number. Not a numerical expression
• Yes. technically a number can also be considered a numerical expression
• Yes. technically a number can also be considered a numerical expression

The answer is "Yes. technically a number can also be considered a numerical expression".

Consider 1+2 and 3xx1. Note that when evaluated, both result in identical numerical value 1+2=3 and 3xx1 = 3.

Are these two different numerical expressions?

• They are two different expressions, evaluating to equal values
• They are two different expressions, evaluating to equal values
• They are identical expressions as they evaluate to equal values

The answer is "They are two different expressions, evaluating to equal values".

Simplify 9-6-:3

• 7
• 7
• 1

The answer is "7". Division has higher precedence over subtraction. So

9-6-:3

=9-2

=7

What is the rule of precedence in numerical expressions?

• multiplication and division have higher precedence over addition and subtraction
• parentheses or brackets have highest precedence
• both the above
• both the above

The answer is "both the above".

Simplify 20-4-3?

• 13
• 13
• 19

The answer is "13".

Two or more operations in the same precedence level are performed from left to right sequence.

20-4-3

= 16-3 =13

Simplify 36-:6-:3. Which one of the following is correct?

•  36-:6-:3 =6 -:3 = 2

•  36-:6-:3 =36-:2 =18

• 2
• 2
• 18

The answer is "2".

The two divisions are in same precedence level. This is to be handled from left to right sequence.

36-:6-:3

= 6-:3 =2

•  It is NOT correct to do =36-:2 =18.

What is the rule of sequence in numerical expressions?

• there is no such thing as rule of sequence
• when multiple operation of same precedence is to be simplified, the operations are performed from left to right sequence
• when multiple operation of same precedence is to be simplified, the operations are performed from left to right sequence

The answer is "when multiple operation of same precedence is to be simplified, the operations are performed from left to right sequence".

Simplify 6-:3xx2

• 4
• 4
• 1

The answer is "4".

The division and multiplication are of same precedence, so it is simplified from left to right.

6-:3xx2

=2xx2

=4

Simplify 6-:(3xx2)

• 4
• 1
• 1

The answer is "1".

The bracket has higher precedence, and so the expression inside bracket is simplified first.

6-:(3xx2)

=6-:6

=1

What is the rule of brackets or parentheses in numerical expressions?

• there is no such thing as rule of brackets
• the subexpression within a bracket or parentheses has the highest precedence
• the subexpression within a bracket or parentheses has the highest precedence

The answer is "the subexpression within a bracket or parentheses has the highest precedence".

In a numerical expression, the precedence order is:
•  division and multiplication in same level same level of precedence
•  addition and subtraction in same level of precedence.

This is abbreviated as BODMAS (Division, Multiplication, Addition, Subtraction) or PEMDAS (Multiplication, Division, Addition, Subtraction).

When multiple operation of same precedence is to be simplified, the operations are performed from left to right sequence.

All these were studied as part of whole numbers and integers. The same applies for fractions.

•  Precedence order BODMAS / PEMDAS

•  Left to Right sequence for same precedence

Let us see some more expressions with fractions.

Solved Exercise Problem:

Simplify 1- 1/6 -:3

• 17/18
• 17/18
• 1/2

The answer is "17/18". Division has higher precedence over subtraction. So

1-1/6-:3

=1-1/18

=17/18

Solved Exercise Problem:

Simplify 6-:3xx(1/2)

• 4
• 1
• 1

The answer is "1".

The division and multiplication are of same precedence, so it is simplified from left to right.

6-:3xx(1/2)

=2xx(1/2)

=1

Solved Exercise Problem:

Simplify 6-:(3xx1/2)

• 4
• 4
• 1

The answer is "4".

The bracket has higher precedence, and so the expression inside bracket is simplified first.

6-:(3xx1/2)

=6-:(3/2)

=4

Solved Exercise Problem:

Simplify 4+(-2/3)-:(1/3)xx(-2)

• 8
• 8
• 5

The answer is "8".

The division and multiplication are of higher precedence over addition. so (-2/3)-:(1/3)xx(-2) is to be simplified first.

In that, the division and multiplication are of same precedence, so it is simplified from left to right.

4+(-2/3)-:(1/3)xx(-2)

=4+(-2)xx(-2)

=4+4

=8.

Solved Exercise Problem:

Simplify 10/7-(-1/7)-2xx(-3/14).

• 4/7
• 2
• 2

The answer is "2". The multiplication is of higher precedence over subtraction and so 2xx(-3/14) is simplified first. Then the two subtraction are in the same precedence level and so they are simplified in the left to right sequence.

10/7-(-1/7)-2xx(-3/14)

=10/7-(-1/7)-(-3/7)

=11/7-(-3/7)

=14/7

=2

Solved Exercise Problem:

Simplify (-1+3/2-1)xx2+(-3)/2-2/4

• -3
• -3
• -1

The answer is "-3"

(-1+3/2-1)xx2+(-3)/2-2/4

=(-2/2 + 3/2 -2/2)xx2+(-3)/2-1/2

=-1/2 xx 2 +(-3)/2-1/2

=(-2)/2 + (-3)/2-1/2

=(-5)/2 -1/2

=(-6)/2

=-3

Solved Exercise Problem:

What is the value of -3-((-1/3)-2xx(1/2))?

• 13/5
• -5/3
• -5/3

The answer is "-5/3".

-3-((-1/3)-2xx(1/2))

brackets take precedence and within the brackets, the multiplication is higher precedence.
=-3-((-1/3)-1)

brackets have higher precedence
=-3-(-4/3)

=-9/3-(-4/3)

simplifying
=-5/3

Solved Exercise Problem:

What is the value of -3/2-(-1/3)-1/4?

• 19/12
• -17/12
• -17/12

The answer is "-17/12".
-3/2-(-1/3)-1/4

LCM of 2, 3, 4 is 12
=-18/12 - (-4/12) - 3/12

left to right sequence
=-14/12-3/12

=-17/12

Solved Exercise Problem:

Simplify 4/5+3/4-:(-3/2)

• -3/10
• -3/10
• 3/10

The answer is "3/10".

4/5+3/4-:(-3/2)

The division is of higher precedence over addition.
=4/5+(-1/2)

=8/10 + (-5)/10

=3/10

Solved Exercise Problem:

Simplify (10-3-2)xx(-1/5).

• -1
• -1
• -15

The answer is "-1".

(10-3-2)xx(-1/5)

The expression inside bracket is simplified first. The two subtraction are in the same precedence level and so they are simplified in the left to right sequence.
=(7-2)xx(-1/5)
=5xx(-1/5)

=-1`

Simplification of Expressions : BODMAS

•  B - Brackets

•  O - Order (exponents, roots, logarithm)

•  D - Division

•  M - Multiplication

•  S - Subtraction

•  And Left to Right sequence for multiple operations of same precedence.

PEMDAS

•  P - Parentheses

•  E - Exponents (roots and logarithm)

•  M - Multiplication

•  D - Division