It looks like a simple math sum but has left people scratching their heads... can you solve it?

It looks simple at first, but this math problem has the internet stumped. Don't be fooled - it demands more brainpower than ...
IEEE

Synthesis of Simultaneous Sum and Difference Patterns in Single-Channel 1-Bit Time-Modulated Array

Abstract: In this letter, a novel synthetic approach for simultaneous sum and difference patterns based on a single-channel 1-bit time-modulated array (TMA) is proposed. A series of asymmetric 1-bit ...