When people have to store intermediate results for multiple tasks concurrently, performance decreases considerably as opposed to when at most one intermediate result has to be stored. Borst, Taatgen and Van Rijn (2010) have shown that a multitasking bottleneck associated with intermediate problem representations can account for this effect. This study investigates whether representing problem representations externally reduces the interference. To this end we extended the experiment in Borst et al. (2010) with a version that required no problem representation. The results show that there is an over-additive increase in response times when both tasks need to store an intermediate representation, as compared to a situation in which at most one task requires an intermediate representation, either because no intermediate representation is needed, or because the intermediate representation is available on the screen. These results suggest that multitasking performance can be improved by presenting intermediate representations in the environment.