TenKey Calculator recommendation - 10key, tape calculator, adding machine

Does anyone have a ten key calculator recommendation? The only app I have found is CalcTape. But I don't want to spend $9.99 if it doesn't do what I need it to do. Basically I want my adding machine features with an app. I work in accounting.

For those of you who are unsure what a "ten key" calculator is, it is a specific mode.

Normal calculator would do: 25 plus 25 plus enter (for equal)

25 + 25 = 50 + 50

With an adding machine/tenkey it shows as when pressing the + button, it is indicating that the number you just entered it a positive. If you were to try this with a normal calculator it does this

+ 25

+ 25

T 50