Question

Find the square of following numbers without actual multiplication.
( i ) 405 (ii)91

Answer 1

Answer:

(i) (405)² = (400+5)²

= (400)²+(5)²+2(400)(5)

=(4²×100²)+(5²)+(4)(10)(100)

=160000+25+4000

=1,64,025

(ii) (91)² = (90+1)²

= (90)²+(1)²+2(90)(1)

= (9²×10²)+(1)+180

=8100+180+1

= 8,281