 # Some special case in multiplication

1. Multiplying two numbers whose difference is
10 and unit digit is 5
)
Example - 25 * 35
First categories in two parts
In first part
2, 3: big number square subtract 1
3^2 - 1 = 9 - 1 = 8
In second part
Always put 75

Example - 155 * 165
= 256 - 1 | 75
= 25575

Dear Raja,

You are on a roll!
Again; great technique for these kinds of multiplications.

If I see 25 * 35, I immediately change to 30^2 - 5^2.
using: (a+b)(a-b) = a^2 - b^2

On this forum you can use Latex commands.
So type \$(a+b)(a-b) = a^2 - b^2\$ to get:
(a+b)(a-b) = a^2 - b^2

If questions is different from them then
Example - 255 * 265
How you do that?

Same way. The middle point between 255 and 265 is 260.
So for:

use a = 260 & b = 5. So:
260^2 - 5^2 = 67600 - 25 = 67575

The way of working is exactly the same. I take 26, square it, add two zeros, then subtract 25 (which is the same as your subtract one and concatenate 75).

But you can easily answer this type of questions with my method
Ex- 265 * 255
676-1 | 75
67575

Like I said;