Method for Finding the Cube of a Two-Digit Number

We will learn the short-cut method for finding the cube of a two-digit number.

Suppose, we have (a + b)³ = a³ + 3a²b + 3ab² + b³.

METHOD:

For finding the cube of a two-digit number with the tens digit = a

and the units digit = b, we make four columns, headed by

a³, (3a² × b), (3a × b²) and b³

The rest of the procedure is the same as followed in squaring a number by the column method.


We simplify the working as; 

a² × a = a³; 

a² × 3b = 3a²b; 

b² × 3a = 3ab²; 

b² × b = b³;


Examples on the method for finding the cube of a two-digit number:

1. Find the value of (29)³ by the short-cut method.

Solution:


Method for Finding the Cube of a Two-Digit Number

Here, a = 2 and b =9.

a² × a = a³;

a² × 3b = 3a² × b;

b² × 3a = 3a × b²;

b² × b = b³

Therefore, (29)³ = 24389



2. Find the value of (71)³ by the short-cut method.

Solution:

Method for Finding the Cube of a Two-Digit Number

Here, a = 7 and b = 1

a² × a = a³;

a² × 3b = 3a² × b;

b² × 3a = 3a × b²;

b² × b = b³

Therefore, (71)³ = 357911



By following the above examples on the method for finding the cube of a two-digit number; we can try to find the value of each of the following using the short-cut method;

1. (25)³

2. (47)³

3. (68)³

4. (84)³


 Cube and Cube Roots

Cube

To Find if the Given Number is a Perfect Cube

Cube Root

Method for Finding the Cube of a Two-Digit Number

Table of Cube Roots


 Cube and Cube Roots - Worksheets

Worksheet on Cube

Worksheet on Cube and Cube Root

Worksheet on Cube Root












8th Grade Math Practice

From Method for Finding the Cube of a Two-Digit Number to HOME PAGE




Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.



New! Comments

Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.




Share this page: What’s this?

Recent Articles

  1. Quarter Past and Quarter To | Quarter Past Hour | Quarter to Next Hour

    Nov 23, 24 03:45 PM

    Quarter Past and Quarter To
    The hands of clock move from left to right. This is called the clock wise motion. When the minute hand is on the right side of the clock, it shows the number of minutes past the hour. When the minute…

    Read More

  2. Half Past an Hour | What does Half Past Mean? | Half an Hour|Half Past

    Nov 23, 24 03:14 PM

    Half Past 1
    We learnt that, one hour is equal to 60 minutes. When one hour is divided into two, it is half an hour or 30 minutes. The minute hand points at 6. We say, 30 minutes past an hour or half past an hour…

    Read More

  3. Telling the Time | Teaching Time | Analogue Clock| Reading Time

    Nov 23, 24 02:51 PM

    Wall Clock
    Teaching time is an interactive activity for telling time. This activity helps students to learn how to read the clock to tell time using the analogue clock. While reading or observing the time on a

    Read More

  4. 2nd Grade Fractions Worksheet | Basic Concept of Fractions | Answers

    Nov 23, 24 12:22 AM

    Divide the Collection into 4 Equal Parts
    In 2nd Grade Fractions Worksheet we will solve different types of problems on fractions, one-whole, one-half, one-third, one-fourth, three-fourth or s quarter. In a fraction, it is important that the…

    Read More

  5. Time Duration |How to Calculate the Time Duration (in Hours & Minutes)

    Nov 22, 24 12:34 AM

    Time Duration Example
    Time duration tells us how long it takes for an activity to complete. We will learn how to calculate the time duration in minutes and in hours. Time Duration (in minutes) Ron and Clara play badminton…

    Read More