EXHIBIT 11.1 EXHIBIT 11.1 INPUT/OUTPUT, INC. COMPUTATION OF EARNINGS PER SHARE May 31, ------------------------ 1997 1996 ---- ---- Weighted average number of common shares outstanding 43,181,486 39,631,464 Dilutive effect of stock options 638,109 1,493,822 ---------- ---------- Weighted average number of common and common equivalent shares outstanding 43,819,595 41,125,286 Net earnings $16,597,000 $38,677,000 Earnings per common share - primary $0.38 $0.94 ---------- ---------- ---------- ---------- Weighted average number of common shares outstanding 43,181,486 39,631,464 Dilutive effect of stock options 661,290 1,622,075 ---------- ---------- Weighted average number of common and common equivalent shares outstanding 43,842,776 41,253,539 Net earnings $16,597,000 $38,677,000 Earnings per common share - fully diluted $0.38 $0.94 ---------- ---------- ---------- ----------