Reduction in performance level following on from brief periods of self-control is referred to as ego depletion. This study aimed to investigate if a brief ego depletion experience would impact upon primary school students working through an online mathematics exercise involving 40 computational trials. Seventy-two students participated in the control group, and 80 students participated in the ego depletion group. The students were 10-14 years of age. A three-minute task involving resistance to distraction was used as the depletion experience. Before each trial, participants selected task difficulty level. Control group students began by working at a moderate difficulty level and then progressed to work on more difficult items. Ego-depleted students chose to work on easy problems throughout. Ego depletion did not markedly affect error rate after the first trial. Depletion effects can be evident in students' academic application through encouraging students to undertake easier options. (Contains 1 table and 1 figure.)