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

Generation of Sum and Difference Radiation Beams with a 2-bit Polarization-Dependent Metasurface

Abstract: This paper describes the generation of sum and difference radiation beams with a 2-bit polarization-dependent (PD) metasurface. A single-layer and cross-shaped dipole unit cell is proposed ...
IEEE

Generalized L-Shaped Array Based on the Difference and Sum Coarray Concept

Abstract: L-shaped array (LA) is traditionally used as two one-dimensional uniform linear arrays (ULAs) for two-dimensional direction of arrival (DOA) estimations. With elevation and azimuth angles ...