You didn’t actually pay the tax or the 10% penalty (you pay a 10% early withdrawal penalty if you are under 59 ½). You had taxes withheld like from your paycheck. You still have to enter the whole gross amount (before taxes were withheld) with your other income to figure out the total tax (and it may put you into a higher tax bracket) and then the withholding is subtracted from the total tax to figure your refund or tax due. The Gross amount shows up on 1040 line 4a or 5a and the taxable amount on 4b/5b. The withholding will show up on 1040 line 25b.
You have to enter the 1099R to see if they took out the right amount of tax withholding. You may end up owing more or getting a refund. And there are other things on the 1099R you need to enter like the Code in box 7.
