Multiplicative Inverse Practice Problems & Exercises

Master multiplicative inverses with step-by-step practice problems. Learn reciprocals, fraction division, and special cases involving 0 and 1.

📚What You'll Master in This Practice Session
  • Find multiplicative inverses of whole numbers, fractions, and decimals
  • Apply the rule a × (1/a) = 1 to solve complex problems
  • Convert division by fractions into multiplication by reciprocals
  • Solve multi-step problems involving multiplicative inverses and mixed operations
  • Understand why zero has no multiplicative inverse and special properties of 1
  • Work with fraction line notation and complex fraction expressions

Understanding Multiplicative Inverse

Complete explanation with examples

Two numbers are multiplicative inverses when their product results in 1 1 .

For example:

12{\Large {1 \over 2}} and 2 2 are multiplicative inverses because 212=1{\Large 2 \cdot {1 \over 2}=1}

Formulation of the Rule for Multiplicative Inverse Numbers:

Whenever a is different from 00, it follows that a1a=1{\Large a\cdot{1 \over a} = 1}

Multiplicative Inverse

Multiplication and Division of Multiplicative Inverses

Division is equivalent to multiplication by its multiplicative inverse,

That is:  213=23=6{\Large {{2 \over {1 \over 3}} = 2 \cdot 3 = 6}}

Because 3 3 is the multiplicative inverse of  13{\Large {1 \over 3}}

Generally: a1b=ab \frac{a}{\frac{1}{b}}=a⋅b

Detailed explanation

Practice Multiplicative Inverse

Test your knowledge with 19 quizzes

\( \frac{25+25}{10}= \)

Examples with solutions for Multiplicative Inverse

Step-by-step solutions included
Exercise #1

(5×410×2)×(35)= (5\times4-10\times2)\times(3-5)=

Step-by-Step Solution

This simple rule is the order of operations which states that multiplication precedes addition and subtraction, and division precedes all of them,

In the given example, a multiplication occurs between two sets of parentheses, thus we simplify the expressions within each pair of parentheses separately,

We start with simplifying the expression within the parentheses on the left, this is done in accordance with the order of operations mentioned above, meaning that multiplication comes before subtraction, we perform the multiplications in this expression first and then proceed with the subtraction operations within it, in reverse we simplify the expression within the parentheses on the right and perform the subtraction operation within them:

What remains for us is to perform the last multiplication that was deferred, it is the multiplication that occurred between the expressions within the parentheses in the original expression, we perform it while remembering that multiplying any number by 0 will result in 0:

Therefore, the correct answer is answer d.

Answer:

0 0

Video Solution
Exercise #2

8×(5×1)= 8\times(5\times1)=

Step-by-Step Solution

According to the order of operations, we first solve the expression in parentheses:

5×1=5 5\times1=5

Now we multiply:

8×5=40 8\times5=40

Answer:

40

Video Solution
Exercise #3

7×1+12= ? 7\times1+\frac{1}{2}=\text{ ?}

Step-by-Step Solution

According to the order of operations, we first place the multiplication operation inside parenthesis:

(7×1)+12= (7\times1)+\frac{1}{2}=

Then, we perform this operation:

7×1=7 7\times1=7

Finally, we are left with the answer:

7+12=712 7+\frac{1}{2}=7\frac{1}{2}

Answer:

712 7\frac{1}{2}

Video Solution
Exercise #4

63×1= ? \frac{6}{3}\times1=\text{ ?}

Step-by-Step Solution

According to the order of operations, we will solve the exercise from left to right since it only contains multiplication and division operations:

63=2 \frac{6}{3}=2

2×1=2 2\times1=2

Answer:

2 2

Video Solution
Exercise #5

12+3×0= 12+3\times0=

Step-by-Step Solution

According to the order of operations, we first multiply and then add:

3×0=0 3\times0=0

12+0=12 12+0=12

Answer:

12

Video Solution

Frequently Asked Questions

What is a multiplicative inverse and how do I find it?

+
A multiplicative inverse (or reciprocal) is a number that when multiplied by the original number equals 1. To find it: for whole numbers like 5, the inverse is 1/5; for fractions like 3/7, flip it to get 7/3; for decimals like 0.25, convert to fraction (1/4) then flip to get 4.

Why doesn't zero have a multiplicative inverse?

+
Zero has no multiplicative inverse because there's no number that when multiplied by 0 gives 1. Since 0 × any number = 0 (never 1), division by zero is undefined in mathematics.

How do I divide by a fraction using multiplicative inverses?

+
To divide by a fraction, multiply by its multiplicative inverse instead. For example: 2 ÷ (1/3) = 2 × 3 = 6, because 3 is the multiplicative inverse of 1/3.

What are common mistakes when working with multiplicative inverses?

+
Common errors include: 1) Confusing additive inverse (-a) with multiplicative inverse (1/a), 2) Forgetting that 1 is its own multiplicative inverse, 3) Trying to find the inverse of zero, 4) Not simplifying fractions before finding inverses.

How do multiplicative inverses help with complex fractions?

+
Complex fractions like (a)/(1/b) become simple multiplication: a × b. This works because dividing by 1/b is the same as multiplying by b (the multiplicative inverse of 1/b).

What's the difference between reciprocal and multiplicative inverse?

+
Reciprocal and multiplicative inverse mean exactly the same thing - they're interchangeable terms. Both refer to the number that when multiplied by the original gives a product of 1.

How do I check if two numbers are multiplicative inverses?

+
Simply multiply them together. If the product equals 1, they are multiplicative inverses. For example: 2/5 × 5/2 = 10/10 = 1, so 2/5 and 5/2 are multiplicative inverses.

Can negative numbers have multiplicative inverses?

+
Yes, negative numbers have multiplicative inverses. For -3, the multiplicative inverse is -1/3 because (-3) × (-1/3) = 1. The inverse of a negative number is also negative.

More Multiplicative Inverse Questions

Continue Your Math Journey

Practice by Question Type