The Unit Digit refers to the digit placed in the one’s place of the particular number, in other words Unit digit is the last digit of any number.
Example – 27895, here 5 is at the end( one’s place) of the number so it will be called unit digit of this number.
Unit digit, When two or more than two numbers are in the form of multiplication –
When two or more than two numbers multiplied then in the result we got a single number then it’s last digit will be called the unit digit of the product.
Example – 234×713 = 166842.
So, here unit digit of the product is 3.
Trick- when two or more than two numbers are in the form of multiplication and we need to find unit digit.
Then it is not mandatory to multiply the entire number because we do not need to know the final product of the number here we only need to focus on the last digit of the final product so if we multiple the last digit of each number then in the final result we will got our unit digits.
As- in the above example we have 234×713 so the last digits of numbers are 4 and 3 so the product of 4 and 3 is 12 and the last digit of 12 is 2. So our unit digit is 2.
Now we will check with some more examples –
Example 1. Find unit digit of 1234× 9876?
Solution – product of 1234 and 9876 is 12186984 so here Unit Digit is 4.
Trick– last digit of 1234 is 4 and last digit of 9876 is 6 so product of 4 and 6 is 24 so, the unit digit is 4.
Unit Digit – 4Ans.
Example 2.Find unit digit of 1496× 893×1287?
Solution – Product of the last digit of each number will result in a Unit digit.
So, 6×3×7 = 18×7
Last digit of 18 is 8 so the product of 8 and 7 results in the unit digit of the question 8×7 = 56, Unit digit = 6 Ans.
Example 3. Find the unit digit of 749+963+458?
Solution – Sum of last digit results to Unit Digit.
So, 9+3+8 = 20, Here the unit digit of 20 is 0.
Unit Digit = 0 Ans.
Example 4. Find the unit digit of 1682 – 241?
Solution – Subtraction of last digit results to unit digit.
So, unit digit will be 2 – 1 = 1
Unit Digit= 1 And.
If here at the place of 2 we have 1 and at the place of 1 we have 2 then different will be -ve so in that type of condition we always took 1 before the 1
Example 5. Find the unit digit of 2347-1969?
Solution – in the previous question we have understood that difference of last digit refers to unit digit but here we got 7-9 so the result will be -2 and we knows unit digit of any number can not be in -ve so whenever we got that type of case then we always take 1 before the first number that is carry forward from it’s previous number so 17- 9 = 8 Unit Digit.
Unit Digit = 8Ans.
Example 6.Find the unit digit of 9528×2793 – 2693×2619
Solution – On taking the Unit digit of each number.
=> 8×3 – 3×9
=> 24 – 27
=> 4 – 7
So, now 1 will be taken before 4.
=> 14 – 7
=> 7 Ans.
Example 7.Find the unit digit of 1683×5284×6294 – √16 ×2859 + 1583×2794?
Solution – On taking
