Print a puzzle sheet at full size on A4 or Letter

Turn scaling off, keep 15 mm of margin, print in black only, and keep the answer page off the sheet you hand out.

The two paper sizes are close enough to look interchangeable and different enough to spoil a print. A4 is 210 by 297 mm. Letter is 216 by 279 mm, which is 8.5 by 11 inches. A4 is about 6 mm narrower and 18 mm taller, so nothing lines up in either direction, and no printer warns you: it scales, shifts or clips and prints anyway.

Fit to page is the setting that costs you the sheet, and it is the default in most print dialogs. Fitting an A4 page onto Letter paper scales it to about 94 per cent, because 279.4 divided by 297 is 0.94. Even when the paper matches the document, the option usually called fit to printable area still shrinks by around 4 per cent to clear the strip at the edge that the printer cannot reach. The setting you are looking for is named differently everywhere: Actual size in Acrobat, Default under Scale in Chrome, and Custom scale set to 100 wherever a number can be typed at all.

Check it once with a ruler instead of trusting the dialog. Print a single page and measure the grid against the size printed in the line under the title; if a 120 mm grid measures 115, something is scaling. The usual hiding place is the printer driver rather than the application: a driver set to Letter with a document set to A4 triggers the fit silently, and both have to be set to the same paper before anything else is worth trying.

Margins are not decoration. Most home printers cannot print within 3 to 5 mm of the paper edge, and many lose considerably more once the driver adds its own safety strip, so below 12 to 13 mm you are gambling. Our sheets keep 15 mm on all four sides for exactly that reason. A word search that loses its right hand column is not a slightly imperfect sheet: it is a sheet on which one of the words can no longer be found.

Print in black and white, and mean it. On an inkjet, colour mode composes black out of cyan, magenta and yellow even when the page is nothing but black rules and black letters, so a class set of thirty word searches drains the expensive cartridges for no visible gain. Choose Greyscale, and where the driver offers it, black ink only. A puzzle sheet has no colour information to lose: the grid lines are 0.25 mm of grey and everything else is black.

Draft quality is the one economy that does cost you something. A 0.25 mm grid rule printed in draft mode breaks up into dots on many inkjets, and a maze whose walls are dotted lines is harder to read than one whose walls are lines. Normal quality in greyscale is cheap enough; draft is for the copy you keep.

The answers are on page 2, and that is the reason not to print double sided by reflex. Printed on the back, the answers are on every child's own sheet, and on 80 gsm office paper they show through when the sheet is held up to the window. Set the page range to 1 for the class, and print page 2 once for yourself.

The same field saves paper rather than wasting it. Thirty pupils, page 1 only, single sided, is thirty sheets; printing everything double sided out of habit is sixty pages on thirty sheets and thirty answer keys handed out by mistake. The page range box sits next to the number of copies in every dialog, and it is the one field worth filling in every single time.

Double sided is right when you are making a booklet of several puzzles for one child. Choose to flip on the long edge for portrait pages: flipping on the short edge prints every second page upside down, which looks like a printer fault and is a setting. Put the answers to all of the puzzles on the last sheet rather than behind each one, and the booklet works the way a magazine does.