The development of symbolic algebra transformedÂ civilization. Since algebra is a recent cultural invention,Â however, algebraic reasoning must build on a foundation ofÂ more basic capacities. Past work suggests that spatialÂ representations of number may be part of that foundation,Â but recent studies have failed to find relations betweenÂ spatial-numerical associations and higher mathematicalÂ skills. One possible explanation of this failure is that spatialÂ representations of number are not activated during complexÂ mathematics. We tested this possibility by collecting denseÂ behavioral recordings while participants manipulatedÂ equations. When interacting with an equationâ€™s greatestÂ [/least] number, participantsâ€™ movements were deflectedÂ upward [/downward] and rightward [/leftward]. ThisÂ occurred even when the task was purely algebraic and couldÂ thus be solved without attending to magnitude (although theÂ deflection was reduced). This is the first evidence thatÂ spatial representations of number are activated duringÂ algebra. Algebraic reasoning may require coordinating aÂ variety of spatial processes.