Along with a number of other hopeful applicants, Estimate Lad tried to make the cut to become a member of the Legion of Super-Heroes. His power to instantly estimate weights, measures, speeds, and numbers did not exactly impress them—particularly since he lacked accuracy in his estimations.
Several of his fellow rejects would become famous by banding together shortly afterwards to become the original Legion of Substitute Heroes. For some reason, Estimate Lad wasn't invited to join their group either. He has not been seen since.