can someone / anyone tell me the trick to solve
501^2 - 400^2
Beginning to feel a little stupid now
It's a difference of two squares, a^2-b^2=(a+b)(a-b).
Incidentally, you are not solving anything. You are simplifying a numerical expression. "Solve" generally means you are obtaining the value of one or more unknown quantities.
Thank you both
(seems so obvious now you've helped me simplify it!)
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