Summations rhymes with:
approximations, animations, approximations, estimations, exclamations, intimations, proclamations, affirmations, animations, approximations, confirmations, dalmatians, estimations, exclamations, formations, information's, informations, intimations, malformations, proclamations, transformations
Summations sounds like:
sanding, sandino's, sandness, scantiness, sending, sentence, sentences, shandong, shantytowns, shunting, smeeting, smoothens, smoothing, smoothness, something, something's, somethings, sometimes, sondheim's, sounding, soundings, soundness, squinting, sumitomo's, sundance