EXHIBIT 16.1 [LETTERHEAD OF DELOITTE & TOUCHE LLP] September 29, 2000 Securities and Exchange Commission Mail Stop 11-3 450 Fifth street NW Washington, DC 20549 Dear Sirs/Madams: We have read and agree with the statements in the Experts section of Amendment No. 2 to Registration Statement No. 333-43208 on Form S-1 of Adaytum Software, Inc. (formerly Adaytum KPS Software Limited) to be filed with the Securities and Exchange Commission on or about September 29, 2000. Yours truly, /s/ Deloitte & Touche LLP