Vedic Math

We have discussed cubes and cube roots, now let us find the cube root of perfect cubes using an easy method. Finding the cube root of perfect cubes is easiest in Vedic math and knowing the cubes of the first 10 natural numbers helps us greatly in these calculations. Let us list them again.

Steps involved in finding the cube root:

• Whenever a cube is given we first split it into groups of 3 digits, starting from the right, just as for a square root we split 2 digits as a group.
• Look at the units digit and from the table confirm the units digit of the cube root.
• Look at the digits in the thousands place and higher. From the table, see which two cubes it falls between and take the smaller cube root as the tens digit.

Let us look at an example:

Find the cube root of 74088

1. Make groups of three digits from the right.

74     088

2. 8 is the units digit. So from the table we see that the cube root will have 2 as units digit.

3. Look at 74. From the table we see that 74 lies between 43 and 53. So we take the smaller number, which is 4.

4. Answer: The cube root of 74088 is 42

Find the cube root of 175616

1. Split the number into 175 and 616.

2. Looking at 616 we know that the units digit of the cube root will be 6.

175 lies between 53 and 63 s so 5 will be the tens digit of the cube,

3. Answer: 56

One thing to remember is that this is applicable only in the case of perfect cubes.

Now let us find the cube root of 912673

912 lies between

93 and 103 so 9 is the tens digit                                     

Answer: 97

Now for some logical thinking. Find the odd man out:

1. (2, 4, 8) (10, 30, 40) (4, 16, 64) (5, 25, 125)

2. (3, 81) (5, 125) (6, 216) (8, 512)

3. (49 + 343) (9 + 81) (25 + 125) (16 + 64)

4. 121 169 132 225

5. 12167 1024 2744 15625

(Hint: All numbers are related to squares and cubes)

Answers:

1. (10, 20, 30) 2. (3, 81)  3. (9+81) 4. 132 5. 1024

Tip of the week: Make yourself familiar with squares and cubes