Cube Root by Successive Subtraction
Cube Root by Successive Subtraction
Like squares of natural numbers, cubes too have some interesting patterns.
.
.
.
Also
From the above pattern, we see that is the sum of the first two numbers of the sequence 1,7,19.37,...Similarly,
is the sum of the first three numbers and so on.In short,these numbers(1,7,19,...)may be obtained by putting n=1,2,3,...in 1+n(n-1) X 3
Thus to find the cube root of a given number, we go on subtracting the numbers of the sequence 1,7,19,37,... till we get a zero. The number of subtractions needed for this purpose is the cube root of the given number.
Illustration: Find the cube root of 343 by successive subtraction.
Solution: Subtract the numbers of the sequence 1,7,19,37,...from 343 till we get zero.
343-1=342
342-7=335
335-19=316
316-37=279
279-61=218
218-91=127
127-127=0
Since we have subtracted seven times to get 0, Hence
Illustration: Find the cube root of 216 by successive subtraction.
While finding the cube root of 729 using the successive subtraction method, find the number obtained after subtraction in 5th step. | |||
| Right Option : B | |||
| View Explanation | |||
What is the number obtained in the sixth step while finding the cube root of 512 by successive subtraction? | |||
| Right Option : D | |||
| View Explanation | |||
What is the number obtained in the eighth step while finding the cube root of 729 by successive subtraction? | |||
| Right Option : D | |||
| View Explanation | |||
Students / Parents Reviews [10]
My experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thBeing a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
Prisha Gupta
8thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
Archit Segal
7thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thIt has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Barkha Arora
10thMy experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
Hiya Gupta
8thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thAbout Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
Shreya Shrivastava
8thAbhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
