*one*explosive, but

*multiple explosives*; how much plastic explosive to use to breach that door or blow that wall, how much is needed for a larger blast radius, and what happens if that pile of missiles is set off, instead of just one.

Blast radius increases by the

*square root*of either the volume, mass, or number of explosive devices (as convenient); explosives constrained to two dimensional expansion by impervious structure have a blast radius that increases by the cubed root of the square of the volume, mass, or number of explosive; explosives constrained to one dimensional expansion by impervious structure has a blast radius that increases

*linearly*with the volume, mass, or number of explosive. How the

*damage*increases is a bit system-dependent, and not clear from the base rules.