Question

What is 18 X 19 i cants figure it out

Answer 1

Answer:

WE can do it in many ways, one is this.

We can write 19 and 18 as 20-8 & 20-1

So we can make it like this:-

(20-2)*(20-1) THIS CAN BE SOLVED BY USIND THE IDENTITY OF (x+a)(x+b)=$x^{2}$+(a+b)x+ab

Here x=20

         a=-2

         b=-1

So,

20^2+ (-2+-1)20+(-2*-1)

=  400+(-2-1)20+ (-2*-1)

=  400+(-3)20 +(-2*-1)

=  400+ -60 +  (2)

=  400 - 60 + 2

=  340+2

= 342

So 18*19=342

And if you are of lower grades follow this method.

Multiply 18 with 20, you will get 360

Now subtract 18 from 360.

WHAT I DID HERE IS ESTIMATED 19 AS 20 AND THEN SUBTRACTED A 18 FROM THE RECEIVED PRODUCT TO PREVENT CHANGE IN VALUE

Answer 2

Answer:

342

Step-by-step explanation: