Posted by Jenny on Friday, May 3, 2013 at 3:40pm.
To square 75, one can multiply (70)(80) and add 25 to that product. Can someone explain how this would work, without calculating?

math  Steve, Friday, May 3, 2013 at 4:29pm
since a^2b^2 = (ab)(a+b)
a^2 = (ab)(a+b)+b^2
75^2 = (755)(75+5)+5^2 = (70)(80)+25