Not to be confused with creatinine. Creatine (/ËkriËÉtiËn/ or /ËkriËÉtÉªn/) is a nitrogenous organic acid that occurs naturally in vertebrates. Its main role is to facilitate recycling of adenosine triphosphate (ATP), the energy currency of the cell, primarily in muscle and brain tissue.
Case 1: You Filed a Previous Year (2014) Tax Return But Do Not Have Access to a Copy of the Return or the AGI. First from the IRS website or call the IRS at 866-704-7388. Here is what you will see on the IRS PIN request site: Note: the image above is for informational purposes and is not interactive.
Two Methods: Determine Adjusted Gross Income for the Year Calculate Federal Taxable Income and Tax. To calculate federal income tax, you need to first estimate your adjusted gross income (AGI). Then, estimated taxable income is determined by subtracting allowable deductions and exemptions from AGI.