Question

Evaluate: (i) $88\times 92$, (ii) $78\times 82$.

Answer 1

(i) $88\times 92$= (90-2)(90+2)
=$(90{)}^2-(2{)}^2$
=8100-4= 8096
(ii) $78\times 82$= (80-2)(80+2)
=$(80{)}^2-(2{)}^2$
=6400-4= 6396