PSC MODEL QUESTION - 21

In our previous tutorial we have learnt shortcut to multiplying any number with 11 without using a pen or pencil or even writing on paper. In this tutorial we will try to learn how to multiply any number with 111.

---

Lets first start with any no. multiplied by 111.

21431 x 111 = ?
In our previous post of X x 11, since it was two 1's, we added 2 No's at a time. Since 111 is three 1's, we must add 3 No's at a time.

Step 1 : Bring down 2 = 2
Step 2 : Add 2 + 1 = 3
Step 3 : Add 2 + 1 + 4 = 7
Step 4 : Omit or cut 2 and add 1 + 4 + 3 = 8
Step 5 : Omit 1 and add 4 + 3 + 1 = 8
Step 6 : Omit 4 and 3 + 1 = 4
Step 7 : Omit 3 bring down 1 = 1
∴ 21431 x 111 = 2378841

---

76859 x 111 = ?

If we get double digits in the process of addition, then apply balancing rule.
∴ 76859 x 111 = 8531349