Question

please explain and solve

Answer 1

69×71=4899
Hope it helps you

Answer 2

10).69×71
we can write it as
(70-1)× (70+1)
it looks like (a-b) (a+b) = a^2 - b^2 formula
a=70, b=1
a^2 =(70)^2 =4900
b^2 =(1)^2 =1
a^2-b^2 =4900-1
=4899 is answer