Measuring things is a huge part of primary school science, so the magnificent Mr Poskitt was very sensible in coming up with a book covering measurement, units, shapes, time measurement and angles. It’s the usual clever mix of light historical context -mostly ancient from Israelites and Archimedes to the Romans – and real insights into fascinating aspects of something that sits nicely between maths and practical science. There’s plenty to keep the reader and interested, and even adults perusing it will have one or two surprises along the way. Because it is very much applied maths, there is also a lot more opportunity to have fun with practical things to try out than has been the case with some of the Murderous Maths series. All in all this is a great addition to the fold.

Only two small moans. This book has been around a while, and it looks like it’s just had a new cover, rather than taking the opportunity to update it a little. For instance, fairly early on someone is worrying he might have to worry how long Concorde is while it’s flying. I suspect most of the audience of this book won’t have a clue what Concorde was. The other shame is that almost straight away the book plunges into one of Poskitt’s long rambling Chicago gangster stories, which are by far the weakest part of his books, and may put some readers off.

But these are minor concerns about an excellent title. I even love the joke on the cover. Alien to girl: ‘NO! I said take us to your ruler!’ Geddit?

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Review by Brian Clegg

A good, sound entry to the Murderous Maths series, though it is slightly puzzling that Scholastic, which already had a codes book in its The Knowledge series – Cracking Codes – should bring out another with a very strong overlap of content.

As usual, Kjartan Poskitt absolutely captures a style that will keep the younger reader interested, and gives lots of practical things to do in code making and breaking, as well as taking us through the history of codes and ciphers. Scrambling, substitution, one time pads and grids all make an entrance, as inevitably do both Mary Queen of Scots and the Enigma Machines (you even get the chance to make your own, Blue Peter-style Enigma machine with bits of paper and a pencil).

There are a few moans, but relatively slight ones. As I think has been commented in another review, the longer story sections, featuring Italian (or Italian/American) gangsters are the weakest – not only is the writing less effective than elsewhere, the story is a bit dull. I found the bit about Turing, which delicately skates around the fact that he committed suicide (and why) confusing – it was probably better to explain the facts, or not mention his life at all. When RSA is mentioned, it’s a shame that the UK’s Clifford Cocks, who devised the approach before the people mentioned, but wasn’t allowed to tell anyone because he worked at GCHQ, doesn’t get a look in. And it would have been good to have a mention of the quantum side of encryption – both that quantum computers could break the public key system, and that quantum encryption has the potential to be workable unbreakable encryption method – but perhaps that is being too fussy.

These are details, though, and the book should provide a great guide both to what codes and ciphers are and where they came from, and how to use them for fun and (hopefully not criminal) profit.

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Review by Brian Clegg

There’s an effect most of us who know people with newborn babies have come across. They will show you a picture of a little, wrinkled prune-like thing and say “isn’t he gorgeous, he’s just so perfect,” or words to that effect. The fact is, only his parents could think so. And something very similar happens with mathematicians and numbers. There’s an awful lot of them out there that only a mathematician could get excited about. Sadly, that includes a fair number (!) Kjartan Poskitt has included in the latest entry in the Murderous Maths sequence.

There’s fun stuff in there too – Fibonacci numbers and the golden ratio, primes, the briefest of glimpses of infinity – but there’s an awful lot that just goes on and on (and on). Even the little stories fail to liven up some of this numerical manipulation. And there are just too many tricks with numbers: “isn’t it amazing – add this to that, take this away, stand on your head and when you look at, it’s the number you first thought of.” Or at least that kind of thing. It’s not that maths is boring, or even that it’s a problem that much of this is useless (something Poskitt makes a big thing of), but rather that there’s lots more interesting stuff out there.

For instance he has a fleeting couple of pages on imaginary numbers. Much more could have been done with these, rather than those endless numerical manipulations.

So there’s good stuff in there, it’s just there’s a fair amount of mediocre too. Still, it should make very effective bedtime reading.

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Review by Peter Spitz

The original Murderous Maths book took on the basics, mostly in and around arithmetic. With that under his belt, Kjartan Poskitt was able to soar into some of the more fun aspects of maths while keeping things basic.

We start off with dimensions, including area and volume and other good stuff, but also with a bit of fun contemplation of what it would be like to live in one or two dimensional spaces. We then move onto speed, but bounce off onto a spot of topology – to be specific Möbius strips. After some fairly painless geometry (not a QED in sight) and a couple of other numerical manipulations like pyramids of numbers (with a reference to Gauss’s trick when at school to quickly add up all the number between 1 and 1,000 (I’d always thought it was 1 and 100)), most of the rest of the book is either a running story about the power of maths featuring rather dumb criminals or mathematical games and puzzles.

In fact in many ways this book is rather like a junior version of one of Martin Gardiner’s excellent books of mathematical puzzles and diversions – and none the worse for that.

Just a few niggles. Philip Reeve’s illustrations are mostly excellent, but there’s one where he clearly wasn’t quite awake. It’s illustrating the measurement needed to work out how much water is need to fill a pond and, erm, the pond is already full of water (so the answer should have been none at all). A little later Poskitt tells us that numbers like the square root of two are called irrational, but doesn’t bother to point out why. This is a great example of where knowing why (an irrational number is one you can’t make out of a ratio of two whole numbers) makes it much easier to remember the obscure terminology.

Finally, there’s one example where the need to be jokey overcomes sense. He comments that making a square of exactly the same area as a circle is “supposed to be impossible, but don’t let that put you off. After all ancient mathematicians couldn’t programme a video or microwave chips, so maybe some things have changed.” This is rather worrying. Firstly ancient mathematicians didn’t know it was impossible, which makes the implication that these days we might be able to do it a strange comparison. Secondly we now know that it definitively isn’t possible because of the nature of pi. It doesn’t matter how good you are at programming the video – and that makes that text downright misleading.

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Review by Peter Spitz

Here’s a strange result. When we reviewed Kjartan Poskitt’s Murderous Maths, it didn’t quite make the four stars, because, the reviewer supposed, it was dealing with basics, and they couldn’t be made quite as exciting as… well, the exciting stuff.

Yet here in a book that could hardly be more basic – it only really deals with addition, subtraction, multiplication and division – Mr Poskitt has produced a better book.

There seem to be too possibilities. Either it’s because Murderous Maths was presumably the first in the series, and Poskitt has got better with practice, or it’s because it’s often easier to make a book interesting on a specific topic than on a wide ranging overview. Either way, this one works very well.

Laying the mathematical groundwork is recognised as being essential these days, and sadly enough, by the time readers reach the age range of this book, many of them still have grasped the basics of arithmetic. Not any more – Poskitt to the rescue! It’s funny, well illustrated by Daniel Postgate (any relation to Oliver Postgate of Noggin the Nog and Captain Pugwash fame?), and relentlessly informative.

There’s one of the best attempts to make times tables approachable I’ve ever seen, and even long division doesn’t look too frightening. Later on there’s a diversion into the history of money, but that’s quite fun, and as the book says, a lot of the everyday arithmetic that matters to as all involves cash.

The only slight irritation comes when we’re dealing with a subtraction like 371-4, which can cause fear and trembling when you first try to take 4 away from 1. Poskitt illustrates this by launching into one of his Italian American mobster stories, which are probably the weakest part of these books. How the subtraction works is revealed in the story, but only in quite an indirect way. There really should be a reinforcer after the story that makes it clear where the extra 1 to turn the 1 at the end of 371 into 11 came from.

Don’t worry, by the way, if your book’s cover says “MURDEROUS MATHS Tricks of the Trade” (see Amazon.com illustration above) – it’s the same book, it has just been retitled, presumably to avoid confusion with other Murderous Maths titles.

Oh and one last good bit of news – not a single upside down answer to a question, our most hated feature of the Scholastic maths and science books. Yee-hah!

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Review by Brian Clegg

The delightfully named Mr Poskitt has written some excellent maths books for Scholastic, but his Gobsmacking Galaxy (“gobsmacking” is roughly “amazing” if it’s not in your vocabulary) is, sadly, fairly ordinary. Unusually, Scholastic has two books on pretty well the same subject (the other being Nick Arnold’s Space, Stars and Slimy Aliens) and neither of them is brilliant.

Part of the problem is that both books feel the need to go on a tour of the solar system, and by the time you’ve reached the third gas giant they’ve become a bit samey. It inevitably results in a big chunk of the book that is a tedious collection of facts. Where are all the good popular science people details? As soon as we’re dealing with space they seem to go out of the window, to the detriment of the readability.

There are also big gaps in there. Some dark gaps, for example. There’s nothing about dark matter – and though the book promises it’ll tell you “what the dark area in between [the stars]” is, in fact it never answers that basic but fascinating question, once you realise how many stars there are out there – why is it black in between the stars?

Like Arnold’s book, this one also perpetuates the myth that the asteroid belt is crammed with floating rocks, and you have to be very lucky to get through it – as opposed to the vast expanse of space with the odd object the typical neighbourhood is like in the belt.

Worst of all, though is one mind-boggling statement. Poskitt tells us that the Earth orbits the Sun in a big circle. Later on he says “most of the planets go around the Sun in a circle, but Mercury actually goes around in an ellipse shape”. Kepler would be turning in his grave. Now admittedly some of the orbits are sufficiently low in eccentricity that they look almost circular – but circular they aint.

Despite this howler (come back epicycles, all is forgiven), on the whole this is a more readable book than Arnold’s and is marginally the better of the two.

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Review by Jo Reed

After an introductory story, Kjartan Poskitt starts, very reasonably with the basics of maths – adding, subtracting and all that. This is essential, but it’s possible slightly older readers will be put off by such basic stuff. They shouldn’t be – he’s soon off onto the next level up, but there is a need to force yourself past those very basic bits.

There’s some nice stuff about early number systems – how hard it would be to do maths with Roman numerals, and even a spot on Archimedes novel system devised to make it possible to calculate the number of grains of sand that would fill the universe. It’s then explained why our number system, and the good old zero, makes things a lot easier. We meet powers, geometry, algebra and more – but in the usual, painless and indeed fun fashion of Poskitt’s friendly maths books, ably helped by Trevor Dunton’s illustrations.

To keep us amused there are deviations into magic squares, prime numbers, time (sorry, time? That’s part of maths because? Oh well…) and more. It’s maths, Jim, but thankfully not as we know it. The only real moan was the occasional use of the Scholastic series’ favourite irritating feature – questions with upside-down answers – but Poskitt doesn’t make any where near as much use of them as Nick Arnold does in the Horrible Science books. Oh, and there’s a rather painful bit where he slags off calculators, which has a good message, but comes across rather like boring old person moaning about the way everyone uses mobile phones these days, where in his day they would send a letter. Or a pigeon. Or something.

Rating this one was quite difficult. It does the job very well – and in that respect deserves four stars. It probably is the best book we’ve seen on the basics of maths. But the fact is, in maths as in most other things, the basics aren’t the most interesting bits, and the three stars reflects the reality that, ably though Poskitt does his job, it’s not the most inspiring topic.

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Review by Peter Spitz

To be honest, this one’s a bit of a disappointment when put alongside Kjartan Poskitt’s sizzling Do You Feel Lucky. This isn’t entirely Poskitt’s fault, as it’s less easy to get excited about fractions and averages than it is about probability (if you don’t think so, I bet you’re wrong).

Nonetheless, the book mostly does a good solid job of introducing fractions with a quick trip into averages as relish on the side to liven things up a bit. One or two of the sections are relatively dull (I found the interminable cake slicing section the worst), but the fact is a fair number of young people have trouble with fractions, and this book certainly brings the vulgar little beasts out into the open.

The only suspect moment was when he talked about Egyptian fractions – these seem to actually be the Greek fraction system used in most Greek maths (the confusion is easy enough, as it became best known when Greek culture was centred on the Egyptian system of Alexandria). What Poskitt doesn’t say is WHY the Greeks (Egyptians) only had fractions with one on the top, except for two thirds. (The answer, if you are interested, is that they used the symbol for the number with a dash over it as a fraction. So 1/3 was gamma with a dash over it (they used letters as numbers). For obscure reasons beta with a dash over it was 2/3, hence the existence of this that he mentions.)

It was also a bit of a shame when he describes the mistakes people make talking about percentages that he didn’t include the type of error heard recently on the BBC TV News. The presenter said something had gone up from 71 to 203, making it a 300% increase (where, in fact it’s a 200% increase).

And one other niggle – he’s very dismissive of decimal fractions, saying they are practically useless – but then he doesn’t mention irrational fractions (that can’t be made out of a ratio of two whole numbers) or transcendentals like pi, for which we haven’t any choice really but to use decimal fractions, so it’s not surprising.

You might think that irrationals and transcendentals are too complex for the audience, but another book from the same stable manages to take in general relativity! Even so, though it’s not the most shining example in the Murderous Maths series, it’s still a very useful introduction to working with fractions, with enough fun to stop it being tedious. As always, those cartoons help enormously (in fact you rather miss them in a couple of short stories that are included in the mix).

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Review by Brian Clegg

** I like this non-fiction book because it is all about maths. I have learned a lot from the book which we can use at school; therefore I will not need a calculator to work out sums. The book was very funny in places and it was set out clearly.

I don’t think anyone who didn’t like maths would enjoy this book as it is set out like a textbook. To explain things more easily I think there needs to be more diagrams so it makes the book easier to understand.

I really enjoyed this book and I would have given it five stars, except I haven’t as it is more like a study book. Therefore I would give the book two stars, because you must really like the subject, otherwise you will end up really bored by the end of the book.

Review by Donna, Age 11

Very broadly there’s two types of science or maths. There’s the sort that makes sense, and is interesting but not necessarily surprising, and there’s the sort that takes you by surprise and makes you go wow! Typical, there’s more of the “wow” factor in physics and maths than some of the other sciences – and this makes for a two-edged sword. Presented right, it’s a great opportunity, but it’s easy to make it totally incomprehensible.

Kjartan Poskitt does a great job in explaining the most everyday bit of maths that is at the same time desperately counter-intuitive – probability. If a coin has been tossed nine times in a row and each time it came up heads, most people will believe the next time it’s more than likely to come up tails. Nope it’s still 50:50, something Poskitt explains with glee.

Compared with some of the other similar Scholastic books (Horrible Science etc.), there is more of a flow to this book – it reads better as a book and less like a series of little articles. It still lacks a bit of the personal edge – it would have been nice to have found a bit more about Pascal and friends – but this made it better popular science, though it pushes up the age range a little in our opinion.

This is some of the most important maths there is for everyday life, yet surprisingly few people understand it – Poskitt’s book should be required reading as it does a brilliant job. To be honest, this is a book many adults could do to read too – it’s that good. It doesn’t make as much use of the cartoons as some of the other books in the format, but they are still very effective.

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Review by Brian Clegg