Question

(4) The unit digit of the cube of 743 is______
(a) 6.
(b) 7.
(c) 3.
(d) 9.
​

Answer 1

Given:

Consider the given number is 743

Find:

We have to find unit digit of cube of 743

Solution:

First find some observation about unit digit

743^1 = 743 = unit digit = 3

743^2 = unit digit will be 3^2 = 9 in the whole 743^2

And 743^3 having unit digit only depend on 3^3 = 27 that is 7 is the unit digit in cube of 743

The correct option is (b).

Answer 2

The unit digit of the cube of 743 is 7.

Given,

Number: 743.

To find,

Unit digit of the cube of 743.

Solution,

Firstly, let's understand the concept of the unit digit of the cube of a given number.

So, when a number is given, then the unit digit of its cube will be the same as the unit digit of the "cube of the unit digit of the number" itself.

For example, consider a number (abc), where 'c' is the unit digit of the number 'abc'. Then,

unit digit of (abc)³ = unit digit of (c)³

So here, we have the given number 743.

The unit digit of (743)³ should be equal to the unit digit of (3)³.

As (3)³ = 27

⇒ unit digit = 7.

So, the unit digit of (743)³ = 7.

Therefore, the unit digit of the cube of 743 is 7.