I saw the word Calculator in the title alongside the words Adding Machine and saw a Mode button and mistakenly assumed it was a mode switch to change to calculator mode from the old ancient adding machine method of number entry where you have to press the add key each and every time to simply put number on the display. Then you get to decide what to do with it in terms of calculation. The instruction sheet shows you how to perform even semi-complex calculations using this method.William Burroughs got the relatively modern adding machine patent way back in 1888. While that’s very old, the first calculator was invented in France 375 years ago.But sometimes you can use it like a regular calculator for simple arithmetic. However, if you are already experienced with this archaic method of numeric data entry, this will no problem whatsoever for you and it works very well. I already anticipate getting a lot of nay votes on this review, but try to see it from my vantage point and either don’t vote at all or give me the benefit of doubt because this user interface is so difficult for me to learn after using normal calculators for 45 years. There a YouTube video teaching you how to use a regular adding machine. I watched the video and understood it, but it will take me a lot of practice to manipulate my brain cells into this different method.I bought a $1.50 on a roll of Staples paper because Canon was so incredibly frugal with the scant roll of paper they supplied. Penny wise and dollar foolish marketing practice as usual. I had to be careful not to use up that short sheet of paper just trying to understand how this device worked. Then I finally learned how to turn off the printer until I learned how to operate it better. Be aware that most adding machine paper is thin 16 pound weight paper. If you get 20 pound weight paper, it is more rigid and less prone to jam. But the one thing that is most important is the paper brightness and almost nobody ever mentions the brightness – also known as how white the paper is. The cheap Staples paper I received was far from white and you can see the difference in how well Canon’s sample paper print looks in comparison – not just the color, but the print quality. But the Canon paper was thin, probably 16 pound weight – perhaps not a problem.This calculator uses an old style typewriter ribbon with half black and half red ink – not monochromatic thermal paper. So you’ll eventually need to buy some black and red ribbon, but another roll of paper is priority one. If you buy genuine Canon ribbon, it’s not cheap – analogous in concept to them supplying ink jet printers with a tiny bit of starter ink in them that is consumed almost immediately. Of course, the black stripe will wear out long before the red ink unless you deal solely in debt.Staples Adding Machine Roll, 2 1/4"W x 150'Lhttps://www.amazon.com/Monroe-Systems-Business-Single-Ply-Paper/dp/B01ITRX1RO/ref=sr_1_1?ie=UTF8&qid=1492546040&sr=8-1&keywords=adding+machine+paper+rolls+20+poundhttps://www.amazon.com/gp/product/B01G7KXGN4/ref=ox_sc_sfl_title_9?ie=UTF8&psc=1&smid=A3BE9164B7XQV0https://www.amazon.com/gp/product/B00T6X4EVI/ref=ox_sc_sfl_title_10?ie=UTF8&psc=1&smid=A2UCS9TMRHXNOSSo I raised this from a 3 star rating to a 4 star rating even though the title is misleading to the uninitiated buyer like me. If you don’t know how the calculator mode is different than the old style adding machine mode, don’t buy this adding machine that just happens to do calculations, but in a confusing way. But if you really need a paper trail, they you will just have to learn how to operate it. You will likely get bizarre and obviously wrong answers printed onto the paper tape if you use it like a calculator. And if you calculate a chain of calculations, you just cannot trust the answer if you slip up even once. It takes a while to adjust to this original method.I wouldn’t mind if they had a button or preferably a switch to operate in modern day calculator mode rather than the method of numeric entry dating back to antiquity. There is a mysterious GT switch which seems to have something to do with calculator mode, but it isn’t consistent. The instruction sheet never mentions what it does along with a lot of other functions. How are you supposed to ever learn what these switches do if they don’t define the different positions? This particular model’s instruction sheet isn’t even listed on the Canon website. They list the predecessor model, which I downloaded. Nothing there either.I would have given it five stars gladly if they offered both calculator and adding machine methods. It’s just a software (firmware) change, so it would not cost a penny extra in production – other than the non-recurring software development cost. It’s not like they don’t already make calculators that have this calculator function. All they had to do was port the calculator software over to this model and adjust the entry sequence. It shouldn’t be difficult. I don’t like the operand (add, multiply, divide, etc.) functions located on the left side of the keyboard either. It should be on the right hand side instead.Oh, a quick way to test a new or used calculator is to list the first three consecutive odd numbers duplicated in a row like this: 113 355. Cut in half like I showed you. Then divide 355 by 113 and the answer is Pi to the 7th fractional digit. The seventh digit comes out to be a 9, but should be a 6. Negligible difference.Oh, they include a mysterious small gray cylindrical plastic piece, but they never mention its purpose. Finally I learned it is a pencil holder that mounts into a tiny hole next to where the power cord goes inside the calculator. It will hole one pencil (not two). I consider pencils almost as obsolete, but my wife still prefers them over ink pens. It will hold a small diameter yellow highlighter, but is too small to hold a standard sized yellow highlighter.I just cannot adapt to what I thought was an obsolete method. If I had know it was this prehistoric style, I would never have accepted it even on the Amazon Vine Program. I got it for her to use in her small business so she could have a paper printout. She was excited at first, but now she refuses to use it at all because she says it is too strange and confusing to operate. She says she will continue to use her computer and print using her regular inkjet printer.I borrowed an adding machine once for a very short while in the 1960s, but I didn’t like it even then. Then came the calculators in the early 1970s and they made sense how to enter and calculate numbers – except for Hewlett Packard’s Reverse Polish Notation (RPN) scientific calculators – where it put the operator before its operands. I wanted and needed their scientific functions, but I despised the RPN entry then as well as now. I never bought it. Read the history in Wikipedia.I worked at Texas Instruments when the calculator was invented. I knew Jerry Merriman, a co-inventor, personally. We both majored in electrical engineering at Texas A&M University. By the way, the original hand held calculator used adding machine paper. I held the original calculator in my own hands. There was no electronic display because compact visible LED panel displays were not invented or available yet. On June 25, 1974, the U.S. Patent office granted Texas Instruments the patent for a Miniature Electronic Calculator. I bought a lot of refurbished 4 function calculators for my friends for $150 each in the middle 1970s. That was huge money back then. But it sure beat a slide rule and doing calculations by hand.