This is one of those things that is the fault of mathematicians being lazy. Its the implied multiplication between the factor and the term in the bracket. Technically 16 is the correct answer according to offical mathematical rules. However everyone just assumes the multiplication between 2 and (2+2) as it makes writing mathematics easyer. Anyone used to algebra will assume the implied multiplication. Even a lot of calculators especially the higher end more scientific ones will say its 1 as well