Canon F-789SGA Calculator, grey

I love this calculator. Not much difference compared to other scientific calculators but I like the design of this one. Durable and nice to type with.

First, this calculator didn't come with thick manuals (as mentioned in another review, but as that review was from 2016 maybe Canon have changed what is supplied, maybe on grounds of cost), instead all I got was (see photo) this fold out, double-sided, manual (or 'user instructions' as Canon call it) which isn't all bad, because a) it's mostly in English not American [it talks of 'maths' and, unfortunately, 'meters'], and b) it's not multi-language.The machine does seen a bit thin, even flimsy, but the hard slide-on case seems up to the job of protecting the keyboard and screen. As for internal accuracy, well it stores pi to 19 places of decimal (rounding up 46 to 5 at place 19) and the square root of two to 18 places, which (if typical) should be enough for almost anyone... However, only ten digits are shown on-screen, excluding the decimal point. Also, if you're wanting to see the value of (say) the square root of 172, then (by default, but this can be changed) the calculator presents you with 2root43 (see photo), not 13.11487705, which you get by pressing the F<->D button.Hopefully the photo of the calc in its case next to a 50p piece will show the thickness, or lack thereof, of both. It is NOT programmable - what do you expect for the price? - but to make up for this it does have stored in it 70 constants and "170 conversion pairs... to convert a number to and from the specified metric units". All the constants and conversion pairs are listed on the User Instructions sheet. It's nice to see both proper and US gallons listed, instead of making assumptions. Well done Canon!A good-quality calculator, then, but the lack of big manuals (which I was looking forward to, and hoping to learn from)and small writing on the User Instructions combine to cost a star, even if this sort of thing is normal these days - at least there IS a physical manual, not a CD containing a PDF...

I was after a replacement for my 20 year old Casio fx-570s, Turns out there are only a handful of sub-£20 scientific calculators that have features I required, at first I had my eye on the Casio FX-991ES PLUS. Then came across the Canon F-789sga which is almost identical, in fact they both use the same screen, but the Canon had more features and was cheaper.I have not been disappointed, although the new calcs are not built like the old models which feel a lot more sturdy and weighty. The Canon makes up for it in features, I love that the calc can express results as fractions and surds when it may be necessary, just imagining how useful that would have been back when I did my Maths A-Levels wouldn't have had to memorise the many surd results that come up in advanced trig.On another note, in my experience when changing between degrees and radians on older calcs usually the MODE button is pushed, but on these new ones I have to push (Shift-MODE) to get to SET-UP where such changes are made; this took me while to figure out.Overall a great calculator I purchased at £13, it's currently £10 which is an absolute steal.

Excellent! This is the strongest calculator I have ever used. The bottoms have soft touching feelings. You don't need to press it much to gain a response on the screen. The apps bottom really has a good using experience.

The 'F-789sga' is exactly the same as the 'Canon X Mark 1 Pro' but is cheaper and has a better keyboard.The thing is also large enough so it won't get lost in the clutter on my desk.An absolute steal at £10.00

This review is for the Canon F-789SGA calculator (note that the model number selection on the website does not have an item for this calculator). I have mixed feelings about this calculator. I chose the calculator because of its high precision. It has 18 digits precision claimed on the specification, but it actually has 20 digit internal precision. Transcendental functions achieve 20 digit precision, which is very nice.Unfortunately, the calculator gives wrong results for some arithmetic calculations. There is an error in the floating point operations that in some cases gives wrong results in the low four digits. For example, in a floating point addition A+B, if the difference in exponents between the two numbers A and B is 16, 17, 18, or 19, then if the low four digits of the larger number are 0000 then the smaller number is not added in (the low four digits of the result stay 0000). This means that the addition 1 + 1E-16 gives exactly 1 instead of 1.0000000000000001. Floating point subtraction has a similar bug. In many calculations where this high precision is not needed, the bug will not be noticed. But in calculations that need high precision, the bug will be seen.Peter Van Roy, professorUniversité catholique de Louvain, Belgium

Bought this for maths teacher training. Lecturer said it was ‘old’ and suggested a different one?

Once it arrived, I thought I may have made a mistake, as it feels ridiculously light and maybe not very sturdy. However, it comes with a sliding protective case, which reassures me of providing some good protection. I've been using it for over one month, and am very pleased. Apart form a slightly long procedure to erase memory slots, everything else is very swift and easy to learn. It has an insane amount of functions. The manuals it comes with (about 5 times the thickness of the calculator itself!) are very thorough, and the examples guide is very handy for getting up to speed with using it.